The symptoms of poisoning depend on the substance and the amount you take in.

Some poisonous substances, such as carbon monoxide, interfere with the blood's ability to carry oxygen. Others, such as bleach, burn and irritate the digestive system.

Parents and carers should be aware of sudden, unexplained illness in young children, particularly if they're drowsy or unconscious, because poisoning could be the cause.

Seek immediate medical advice if you think someone has swallowed a poisonous substance.

Find out what to do if you think someone has been poisoned.

General symptoms

General symptoms of poisoning can include:

• feeling and being sick
• diarrhoea
• stomach pain
• drowsiness, dizziness or weakness
• high temperature of 38C (100.4F) or above
• chills (shivering)
• loss of appetite
• headache
• irritability
• difficulty swallowing (dysphagia)
• breathing difficulties
• producing more saliva than normal
• skin rash
• blue lips and skin (cyanosis)
• burns around the nose or mouth
• double vision or blurred vision
• mental confusion
• seizures (fits)
• loss of consciousness
• coma, in severe cases

Signs of a medication or drug overdose

Medication overdoses are the most common type of poisoning in the UK.

If someone takes too much of a medicine, they may experience symptoms specific to the medication taken, as well as the more general symptoms listed above.

Some of the most common medicines or drugs involved in cases of poisoning are listed below.

Paracetamol

Paracetamol is a widely used over-the-counter painkiller.

Specific signs of paracetamol poisoning include:

• yellowing of the skin and the whites of the eyes (jaundice)
• loss of co-ordination
• low blood sugar (hypoglycaemia), which can cause symptoms including sweating, trembling and irritability

Aspirin

Aspirin is an anti-platelet medicine that thins the blood and reduces the risk of blood clots forming.

Specific signs of aspirin poisoning include:

• sweating
• rapid breathing
• ringing in the ears (tinnitus)
• temporary hearing loss

Tricyclic antidepressants

Tricyclic antidepressants are used to treat depression, as well as a number of other mental health conditions, such as panic disorder and obsessive compulsive disorder (OCD). Some types of tricyclic antidepressants can also be used to treat nerve pain.

Specific signs of poisoning with tricyclic antidepressants include:

• excitability
• dry mouth 
• large pupils
• irregular or rapid heartbeat
• low blood pressure, which can cause symptoms including lightheadedness and fainting

Selective serotonin reuptake inhibitors (SSRIs)

SSRIs are a newer type of antidepressant that are also used to treat mental health conditions such as OCD and anxiety disorder.

Specific signs of SSRI poisoning include:

• feeling agitated
• tremor (shaking)
• uncontrolled movement of the eyes (nystagmus)
• severe muscle tension

Beta-blockers

Beta-blockers are used to treat a number of conditions that affect the heart or blood, such as high blood pressure (hypertension), angina and heart failure.

Specific signs of poisoning with beta-blockers include:

• low blood pressure, which can cause symptoms such as lightheadedness and fainting
• a slow heartbeat (below 60 beats per minute)

Calcium-channel blockers

Calcium-channel blockers are used for the treatment of high blood pressure and angina.

Specific signs of calcium-channel blocker poisoning include:

• feeling agitated
• low blood pressure, which can cause symptoms such as lightheadedness and fainting
• chest pain
• a slow heartbeat (below 60 beats per minute)

Benzodiazepines

Benzodiazepines are a type of tranquiliser, often used on a short-term basis to treat anxiety and sleeping problems (insomnia).

Specific signs of poisoning with benzodiazepines include:

• co-ordination and speech difficulties
• uncontrolled movement of the eyes (nystagmus)
• shallow breathing
• drowsiness

Opioids

Opioids are a type of stronger painkiller used to treat moderate to severe pain. They include codeine and morphine, as well as the illegal drug heroin.

Specific signs of opioid poisoning include:

• small pupils
• shallow breathing
• drowsiness

Stimulant overdose

If you take too much of a stimulant-like drug, such as cocaine, amphetamine, crack or ecstasy, overdose signs can include:

• anxiety and paranoia
• restlessness or agitation
• hallucinations
• high temperature
• chest pain
• rapid breathing
• irregular or fast heartbeat

Cannabis overdose

If you smoke (or eat) too much cannabis, you may experience the following symptoms:

• paranoia
• hallucinations
• numbness in your arms and legs

Being poisoned can be life-threatening. If someone has swallowed a poisonous substance, don't try to treat them yourself – seek medical help immediately.

If they're showing signs of being seriously ill, dial 999 to request an ambulance or take them to your local A&E department.

Symptoms associated with serious poisoning include:

• being sick
• dizziness
• sudden, noticeable heartbeats (palpitations)
• breathing difficulties
• uncontrollable restlessness or agitation
• seizures (fits)
• drowsiness or loss of consciousness

Call NHS 111 for advice if a person who's been poisoned doesn't appear to be seriously ill.

Helping someone who's conscious

If you think someone has been severely poisoned and they're still conscious, ask them to sit still and stay with them while you wait for medical help to arrive.

If they've been poisoned by swallowing something, try to get them to spit out anything that is remaining in their mouth.

If a harmful substance has splashed onto their skin or clothes, remove any contaminated items and wash the affected area thoroughly with warm or cool water. Be careful not to contaminate yourself in the process.

Helping someone who is unconscious

If you think someone has swallowed poison and they appear to be unconscious, try to wake them and encourage them to spit out anything left in their mouth. Don't put your hand into their mouth and don't try to make them sick.

While you're waiting for medical help to arrive, lie the person on their side with a cushion behind their back and their upper leg pulled slightly forward, so they don't fall on their face or roll backwards. This is known as the recovery position.

Wipe any vomit away from their mouth and keep their head pointing down, to allow any vomit to escape without them breathing it in or swallowing it. Don't give them anything to eat or drink.

If the person isn't breathing or their heart has stopped, begin cardiopulmonary resuscitation (CPR) if you know how to.

Poisonous fumes

If you think someone has inhaled poisonous fumes, assess the situation first and don't put yourself in danger.

If the person is conscious, encourage them to make their way out of the contaminated area, if at all possible. Once they're out into fresh air, check to see if they're OK and call 999 if they have signs of serious poisoning (see above).

Dial 999 to request an ambulance if the person is unconscious or unable to get out of the affected area. Don't enter any enclosed areas to remove the person yourself because toxic gases and fumes can be very dangerous if inhaled.

How to help medical staff

Medical staff will need to take a detailed history to effectively treat a person who's been poisoned. When the paramedics arrive or when you arrive at A&E, give them as much information as you can, including:

• what substances you think the person may have swallowed
• when the substance was taken (how long ago)
• why the substance was taken – whether it was an accident or deliberate
• how it was taken (for example, swallowed or inhaled)
• how much was taken (if you know)

Give details of any symptoms the person has had, such as whether they've been sick.

Medical staff may also want to know:

• the person's age and estimated weight
• whether they have any existing medical conditions
• whether they're taking any medication (if you know)

The container the substance came in will help give medical staff a clear idea of what it is. If you don't know what caused the poisoning, blood tests may be needed to identify the cause.

Hospital treatment

Some people who have swallowed a poisonous substance or overdosed on medication will be admitted to hospital for examination and treatment.

Possible treatments that can be used to treat poisoning include:

• activated charcoal – sometimes used to treat someone who's been poisoned; the charcoal binds to the poison and stops it being further absorbed into the blood
• antidotes – these are substances that either prevent the poison from working or reverse its effects
• sedatives – may be given if the person is agitated
• a ventilator (breathing machine) – may be used if the person stops breathing
• anti-epileptic medicine – may be used if the person has seizures (fits)

Tests and investigations

Investigations may include blood tests and an electrocardiogram (ECG).

A blood test can be used to check the levels of chemicals and glucose in the blood. They may be used to perform a toxicology screen (tests to find out how many drugs or how much medication a person has taken), and a liver function test, which indicates how damaged the liver is.

The Lab Tests Online UK website has more information about liver function tests.

An ECG is an electrical recording of the heart to check that it's functioning properly.

Further information

For more information about treating specific types of poisoning see:

• treating food poisoning
• treating alcohol poisoning
• treating carbon monoxide poisoning

Deliberate poisoning

If you or someone you know has poisoned themselves as an act of deliberate self-harm or an attempt at suicide, psychiatric help may be necessary.

Read more about getting help for self-harm and getting help if you're feeling suicidal.

The most common form of poisoning in the UK is from medication.

To reduce the risk of accidental poisoning by medication:

• always carefully read the patient information leaflet that comes with your medication and take the exact dose recommended
• if you're unsure about any of the instructions or have further questions, ask your pharmacist or GP for advice
• some medications shouldn't be taken with alcohol or certain types of food – check if this is the case for your medication
• some medications can react unpredictably if taken with other medications, including herbal remedies – always check before combining different medications.
• never take a medication that's been prescribed for someone else
• keep all medication out of reach of children

Keeping children safe

Children under 5 years of age have a particularly high risk of poisoning. To reduce the risk for your children:

• make sure all medicines, cleaning products, chemicals and potentially harmful cosmetics, such as nail varnish, are locked away out of the sight and out of reach of children
• don't store medicines, cleaning products or chemicals near food
• keep all chemicals in their original containers and never put medicines or chemicals, such as weedkiller, in soft drinks bottles
• when encouraging children to take medicine (when they're sick), don't refer to tablets as sweets
• don't leave old medicines lying around – take them to your local pharmacist to dispose of safely
• keep cigarettes and tobacco out of the reach of children and don't smoke in front of children
• small batteries, such as those used for television remote controls, can be easily swallowed, so keep them out of the reach of children
• whenever possible, buy medicines that come in child-resistant containers
• rinse out medicine or cosmetic containers and dispose of them in a place where children can't reach them
• don't take or give medicines in the dark, to avoid taking an incorrect dosage

If you have young children, be extra careful when you have guests to stay or when you go to visit other people. If your friends and relatives don't have children, they may not keep certain items out of reach and their home is unlikely to be childproof.

Keep an eye on your children at all times and politely ask guests to keep items such as alcohol and cigarettes out of their reach.

Read more about preventing accidents to children in the home.

Further information

For more information about preventing specific types of poisoning see:

• preventing food poisoning
• preventing alcohol poisoning
• preventing carbon monoxide poisoning