theophylline and theobromine, which are chemicals similar to caffeine.
In this Article
headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, and confusion.
Special Precautions & Warnings:Pregnancy and breast-feeding: If you are pregnant or breast-feeding, oolong tea in small amounts is probably not harmful. However, do not drink more than 2 cups a day of oolong tea. That amount of tea contains about 200 mg of caffeine. Too much caffeine during pregnancy might cause premature delivery, low birth weight, and harm to the baby. Too much caffeine during breast-feeding might cause irritability and increase bowel movements in nursing infants.
Children: Caffeine is probably safe in children in amounts commonly found in foods.
Anxiety disorders: The caffeine in oolong tea might make anxiety disorders worse.
Bleeding disorders: Some research suggests that caffeine might slow blood clotting. Though this research was not done in humans, there is still some concern that caffeine might make bleeding disorders worse.
Heart conditions: Caffeine in oolong tea can cause irregular heartbeat in some people.
Diabetes: Some research suggests that the caffeine in oolong tea may affect the way people with diabetes process sugar and may complicate blood sugar control. Caffeine has been reported to both increase and decrease blood sugar. There is also some interesting research that suggests caffeine may make the warning signs of low blood sugar in people with type 1 diabetes more noticeable. This might increase the ability of people with diabetes to detect and treat low blood sugar. However, the downside is that caffeine might actually increase the number of low-sugar episodes. If you have diabetes, talk with your healthcare provider before using oolong tea.
Diarrhea. Oolong tea contains caffeine. The caffeine in oolong tea, especially when taken in large amounts, can worsen diarrhea.
Irritable bowel syndrome (IBS): Oolong tea contains caffeine. The caffeine in oolong tea, especially when taken in large amounts, can worsen diarrhea and might worsen symptoms of IBS.
Glaucoma: The caffeine in oolong tea increases the pressure inside the eye. The increase occurs within 30 minutes and lasts for at least 90 minutes.
High blood pressure: The caffeine in oolong tea might increase blood pressure in people with high blood pressure. However, this doesn't seem to happen in people who regularly drink oolong tea or other caffeinated products.
Weak bones (osteoporosis): Drinking oolong tea can flush out calcium in the urine. That can affect bone health. If you have osteoporosis, don't drink more than 3 cups of oolong tea per day. Consider taking calcium supplements to make up for the calcium that is flushed out. If you have a genetic condition that harms the way your body processes vitamin D, get medical advice before consuming a lot of caffeine.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.