Taking 4 paracetamol tablets by mistake is unlikely to cause harm if these are within the recommended dose range for a single intake. However, it depends on the dose per tablet and your total intake in 24 hours. Typically, the maximum safe dose for adults is up to 8 tablets of 500 mg each in 24 hours (total 4 grams). Taking slightly more than the recommended dose once usually does not cause serious issues but taking large amounts or repeated overdoses can cause liver damage, which can be serious and life-threatening.

Immediate effects of taking 4 tablets:

• Usually no severe symptoms if within the single-dose limit.
• Mild side effects like nausea or stomach upset may occur.
• If taken with other paracetamol-containing medicines, risk of overdose increases.

Risks of paracetamol overdose:

• Overdose symptoms usually appear 24 hours after taking too much.
• Symptoms include abdominal pain, nausea, vomiting, drowsiness, or more severe effects like seizures or coma in major overdose.
• Liver damage is the main serious risk from overdose, which can lead to liver failure and even death if untreated.
• Treatment with an antidote is possible and effective if given early after overdose.

What to do if taken by mistake:

• Check the total amount of paracetamol taken in 24 hours.
• If unsure or if you exceed the recommended daily dose, seek medical advice immediately.
• Contact emergency services or a poison control center if symptoms of overdose appear or if a large dose was taken.
• Do not wait for symptoms to appear; early treatment is crucial.

In summary, taking 4 paracetamol tablets once by mistake is usually not harmful if this does not exceed the daily recommended dose, but caution is essential, and medical advice should be sought if there is any concern or additional doses are taken.