Common Doxycycline Side Effects

Like all medications, Doxycycline can cause side effects. The good news is that most people tolerate it well, and the most common side effects are mild. Here is what you might experience:

Stomach and Digestive Issues

The most frequently reported side effects involve your stomach and digestive system:

• Nausea — the most common complaint. Taking Doxycycline with food can help.
• Vomiting — less common but possible, especially on an empty stomach
• Diarrhea — usually mild and temporary
• Abdominal pain or cramping — typically goes away as your body adjusts
• Loss of appetite — usually mild

Unlike many other tetracycline antibiotics, Doxycycline can be taken with food without significantly reducing its effectiveness. If stomach upset is bothering you, try taking it with a meal.

Sun Sensitivity (Photosensitivity)

Doxycycline makes your skin more sensitive to sunlight. This is one of the most important side effects to know about. You may sunburn more easily or develop a rash in sun-exposed areas. To protect yourself:

• Wear sunscreen with SPF 30 or higher every day
• Wear protective clothing and a hat when outdoors
• Avoid tanning beds
• Limit time in direct sunlight, especially between 10 a.m. and 4 p.m.

Esophageal Irritation

Doxycycline can irritate your esophagus (the tube connecting your throat to your stomach) if the pill gets stuck. To prevent this:

• Take it with a full glass of water
• Stay upright (do not lie down) for at least 30 minutes after taking it
• Do not take it right before bed

Other Common Side Effects

• Headache
• Vaginal yeast infection — antibiotics can disrupt normal bacteria and allow yeast overgrowth

Serious Side Effects: When to Call Your Doctor

Serious side effects from Doxycycline are uncommon, but they can happen. Contact your doctor right away or seek emergency care if you experience any of the following:

Severe Allergic Reaction

Signs include:

• Hives, rash, or severe itching
• Swelling of the face, lips, tongue, or throat
• Difficulty breathing or swallowing
• Feeling dizzy or faint

A severe allergic reaction (anaphylaxis) is a medical emergency. Call 911 immediately.

Clostridioides difficile (C. diff) Infection

Antibiotics can disrupt the normal bacteria in your gut and allow a dangerous bacteria called C. diff to grow. Watch for:

• Severe or watery diarrhea that does not stop
• Stomach cramps or tenderness
• Fever
• Blood or mucus in your stool

C. diff can develop during treatment or even weeks after you stop taking Doxycycline. Do not try to treat severe diarrhea on your own — call your doctor.

Intracranial Hypertension (Pseudotumor Cerebri)

This is a rare but serious condition where pressure builds up inside your skull. Symptoms include:

• Severe or persistent headache
• Blurred vision or vision changes
• Ringing in the ears
• Nausea and vomiting

This risk increases if you are also taking isotretinoin (Accutane) or other retinoid medications. Tell your doctor if you are on any of these drugs before starting Doxycycline.

Liver Problems

Rarely, Doxycycline can affect the liver. Seek medical attention if you notice:

• Yellowing of the skin or eyes (jaundice)
• Dark-colored urine
• Severe fatigue
• Upper right abdominal pain

Blood Disorders

In very rare cases, Doxycycline can affect blood cells. Contact your doctor if you experience unexplained bruising, bleeding, or signs of anemia (extreme tiredness, pale skin).

Side Effects in Special Populations

Children Under 8

Doxycycline can cause permanent tooth discoloration (yellow-gray-brown staining) and enamel problems in children under age 8. For this reason, it is generally avoided in young children unless the benefit clearly outweighs the risk — such as for Rocky Mountain spotted fever or other serious tick-borne illnesses.

Pregnant Women

Doxycycline is classified as Category D in pregnancy. It can cause tooth discoloration and affect bone development in the fetus. It should not be used during the second and third trimesters of pregnancy. If you become pregnant while taking Doxycycline, contact your doctor immediately.

How to Manage Common Side Effects

Most side effects are manageable with simple steps:

• Nausea: Take with food. Avoid spicy or greasy meals around dosing time.
• Sun sensitivity: Wear sunscreen and protective clothing daily.
• Esophageal irritation: Take with a full glass of water and stay upright for 30 minutes.
• Yeast infections: Over-the-counter antifungal treatments can help. Talk to your pharmacist.
• Diarrhea: Stay hydrated. Probiotics may help. If it becomes severe or bloody, call your doctor.

Want to learn more about how Doxycycline works in your body? Read our plain-English guide to Doxycycline's mechanism of action. If you are concerned about interactions with other medications, check our Doxycycline drug interactions guide.

When to Call Your Doctor vs. When to Go to the ER

Here is a quick reference:

Call your doctor:

• Side effects that are bothersome and not going away
• Moderate diarrhea lasting more than 2 days
• Skin rash or increased sun sensitivity
• Vaginal yeast infection symptoms

Go to the ER or call 911:

• Signs of a severe allergic reaction (swelling, trouble breathing)
• Severe or bloody diarrhea
• Sudden severe headache with vision changes
• Signs of liver problems (yellowing skin, dark urine)

Bottom Line

Doxycycline is generally well tolerated, and most side effects are mild and manageable. The most important things to remember are to take it with food and water, protect yourself from the sun, and know the warning signs that need medical attention. If you have concerns about side effects, talk to your doctor or pharmacist.

Looking for general information about this medication? Read our guide on what Doxycycline is and how it is used. Need to fill your prescription? Use MedFinder to find Doxycycline in stock at a pharmacy near you.