Guide
How to read a medicine's package leaflet
Prepared by the LekCheck team · Last reviewed: 2026-07-25 · How we create our content
The package leaflet (the patient information leaflet) is the official document that comes with every medicine and explains how to use it safely. It looks long and technical, but it has a clear structure. Below we explain its main sections and what to pay attention to. Always read the leaflet before first use and keep it while you are using the medicine.
This guide was prepared by the LekCheck team and has not been reviewed by a doctor or pharmacist. This article is for general information only and is not medical advice, diagnosis, or treatment. Do not start, stop, or change any treatment without consulting a doctor or pharmacist.
What the medicine is for and when not to take it
At the start, the leaflet describes what the medicine is and which conditions it is used for (indications), as well as when it should NOT be taken (contraindications) — for example with an allergy to an ingredient, certain conditions, pregnancy or breastfeeding. Check these sections before you start, especially if you have chronic conditions.
How to take it — dose and method
The dosage section says how much, how often and in what way the medicine is taken, including for children and older people if applicable. Follow the stated dose and duration; 'more' does not mean 'better'. Note instructions such as 'with food', 'not with alcohol' or 'not with other products containing the same ingredient'.
Side effects and interactions
The leaflet lists the possible adverse reactions — from common to rare — and explains for which of them to see a doctor. The interactions section lists medicines, foods or conditions the medicine should not be combined with. Tell the doctor and pharmacist everything you take, including supplements.
Storage and expiry date
At the end, the leaflet states how to store the medicine (e.g. below a certain temperature, away from light or children) and until when it is usable. Do not use a medicine that is expired or has changed appearance. If you have questions about a specific instruction, ask a pharmacist.
Frequently asked questions
Do I need to read the leaflet every time?
It is enough to read it carefully before first use and keep it for reference. Review it again if your condition changes, if you start another medicine or if you are unsure about the dose. If unsure, a pharmacist can explain a specific section.
What does 'contraindications' mean?
Contraindications are situations in which the medicine should not be taken because the risk outweighs the benefit — for example an allergy to an ingredient, a certain condition or pregnancy. If you fall into such a category, do not take the medicine without consulting a doctor or pharmacist.
Will I get all the side effects listed?
No. The leaflet lists all the possible adverse reactions observed with use, but most people do not get all or even most of them. The section states how common they are. It is important to know at which signs to see a doctor and which are rare but serious.
What should I do about a side effect?
For a mild and expected side effect, follow the instructions in the leaflet. For a severe or unusual reaction (e.g. difficulty breathing, a rash, severe swelling), stop taking it and seek emergency help. Reporting adverse reactions also helps medicine safety.
I lost the leaflet — what should I do?
Do not take the medicine 'from memory' if you are unsure. Leaflets for authorised medicines are usually available online through the regulator (in Bulgaria — the BDA/ИАЛ), and a pharmacist can print or explain the key information. If unsure about the dose, always check.