Doxycycline: Common Uses and Important Cautions

What doxycycline is

Doxycycline is an antibiotic from the tetracycline group. It is used to treat a range of bacterial infections and is also prescribed for some non-infection conditions, such as certain types of acne and rosacea, and as malaria prevention in some travellers. Like all antibiotics, it works only against bacteria and has no effect on viral illnesses such as colds and most coughs.

What it is commonly used for

Depending on local guidance, doxycycline may be prescribed for:

• Certain chest and respiratory infections
• Some skin infections and inflammatory acne
• Certain sexually transmitted infections
• Some tick-borne infections
• Malaria prevention for travel to certain regions

Your doctor chooses the antibiotic based on the likely bacteria and your individual circumstances, which is why doxycycline is not appropriate for every infection.

Photosensitivity: take the sun seriously

A well-known caution with doxycycline is photosensitivity. The medicine can make your skin much more sensitive to sunlight and ultraviolet light, so you may burn far more easily than usual. While taking it:

• Limit time in strong sunlight
• Cover up and use a high-factor sunscreen
• Avoid sunbeds and tanning lamps

This is especially relevant on summer holidays or for those taking it long-term for acne.

Not for pregnancy or young children

Doxycycline is generally not used during pregnancy or breastfeeding, and is avoided in young children (typically under a certain age set by local guidance). This is because tetracyclines can affect developing teeth and bones, including causing permanent tooth discolouration. Tell your doctor if you are pregnant, think you might be, or are breastfeeding so a suitable alternative can be chosen.

How to take it well

To reduce side effects and help it work:

• Take it with plenty of water and stay upright for a while afterwards, as it can irritate the gullet.
• Certain products, such as those containing calcium, iron, magnesium, or some indigestion remedies, can stop doxycycline being absorbed properly. Check the leaflet for timing advice.
• Follow the instructions about food, as guidance can vary between products.

Finish the course

Unless your doctor tells you otherwise, complete the full course even if you feel better partway through. Stopping early can leave some bacteria alive, allowing the infection to return and contributing to antibiotic resistance. To understand why this matters so much, see our guide on antibiotic resistance explained.

Allergies and side effects

Tell your doctor if you have ever had an allergic reaction to a tetracycline antibiotic. Stop and seek urgent help if you develop signs of a serious allergic reaction, such as swelling of the face or throat, a widespread rash, or difficulty breathing.

More common side effects include nausea, stomach upset, and diarrhoea. If you develop severe or persistent diarrhoea, contact your doctor, as it can occasionally signal a more serious bowel problem.

Using antibiotics responsibly

Only take doxycycline when prescribed for you, never share it, and return any leftovers to a pharmacy. For related products see the antibiotics range, or browse shop all. Used correctly and under guidance, doxycycline is a valuable antibiotic for the right infections.

General information only — not medical advice. Always read the patient information leaflet and consult a doctor or pharmacist before starting any medication.