--- title: "Black Tea: Benefits, Uses & Side Effects | Herbadex" description: "Its caffeine and L-theanine increase attention and alertness. Observational studies link regular tea drinking to lower cardiovascular risk." language: en url: https://herbadex.com/en/herb/black-tea/ source: Herbadex (https://herbadex.com) --- [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) # Black Tea Camellia sinensis A Strong clinical evidence Its caffeine and L-theanine increase attention and alertness. Observational studies link regular tea drinking to lower cardiovascular risk. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Heart & Circulation](https://herbadex.com/en/for/heart-circulation/) Image: Herbadex Botanik Stüdyosu · Özel Üretim Pregnancy **Caution** Breastfeeding **Caution** Children **Caution** Drug interactions **Interaction reported** ## At a glance Black tea is made by fermenting (oxidising) Camellia sinensis leaves; Turks drink the most tea per person in the world. A glass contains 40–70 mg of caffeine, which is well shown to improve attention and alertness. In large observational studies, people drinking 2–3 cups a day had slightly lower cardiovascular risk; this is not proof of cause and effect. **Parts used:** leaves **Key constituents:** Caffeine (40–70 mg/cup), Theaflavins & Thearubigins, L-Theanine Updated: October 15, 2026 ℹ Compiled from standard pharmacognosy references and clinical literature summaries where no formal EMA monograph exists. ## What is it used for? - A Strong clinical evidence Caffeine and L-theanine increase attention and alertness. \[2\] - B Limited clinical evidence Observational studies link regular tea drinking to lower cardiovascular disease risk. \[2\] ## How is it used? ### Tea Steep in a teapot for 5–10 minutes; avoid very strong and very hot tea. **Amount:** 2–4 glasses daily \[2\] ## Safety & interactions - Very hot drinks (over 65 °C) increase the risk of oesophageal cancer; let tea cool a little. - Tea tannins reduce iron absorption; people with iron deficiency should not drink it with meals. - In pregnancy, keep caffeine under 200 mg a day (about 3–4 light glasses). - People with sleeplessness or palpitations should avoid it in the evening. \[2\] \[1\] ### Drug interactions | Medicine / substance | Effect | Severity | | --- | --- | --- | | Iron supplements | Reduces absorption; leave 1–2 hours apart. [1] | Moderate | | Other caffeinated products, stimulant drugs | Caffeine effects may add up. [1] | Minor | | Lithium, clozapine, theophylline | Caffeine may affect their levels. [1] | Minor | ### Side effects - Sleeplessness, palpitations (in excess) - Heartburn - Tooth staining #### ⚕ When to see a doctor - If high fever, shortness of breath or purulent/bloody phlegm develops - If symptoms do not improve within 1–2 weeks or worsen - If severe abdominal pain, jaundice, rash or allergic reaction occurs ## Did you know? Turks drink about 3 kg of tea per person a year, the highest in the world. \[2\] ## Frequently asked questions How many glasses of tea a day? For healthy adults the caffeine limit is about 400 mg, roughly 6–8 glasses of tea. Does tea cause iron deficiency? Drunk with meals it reduces iron absorption; between meals is better. Light or strong tea? Light tea has less caffeine and tannin; better for people with iron deficiency or a sensitive stomach. ## Sources 1. [Herbs at a Glance: Evidence-Based Fact Sheets on Botanical Products](https://www.nccih.nih.gov/health/herbsataglance) NIH NCCIH · 2024 2. [EFSA Compendium of Botanicals Reported to Contain Naturally Occurring Substances of Possible Concern](https://www.efsa.europa.eu/en/data-report/compendium-botanicals) EFSA · 2022 ### Cite This Page Black Tea (Camellia sinensis). Herbadex — Doğal Şifa Rehberi (2026). https://herbadex.com/en/herb/black-tea/ ## Related guides and comparisons - [Green Tea or Black Tea?](https://herbadex.com/en/compare/green-tea-vs-black-tea/) ## On this page At a glance What is it used for? How is it used? Safety & interactions Did you know? Frequently asked questions Sources Related herbs ## Related herbs ### [Ginkgo Leaf](https://herbadex.com/en/herb/ginkgo/) A Strong clinical evidence Ginkgo biloba Standardised ginkgo extract may help age-related cognitive decline and mild dementia; bleeding risk and interactions call for caution. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Heart & Circulation](https://herbadex.com/en/for/heart-circulation/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Green Tea](https://herbadex.com/en/herb/green-tea/) T Traditional use Camellia sinensis Green tea is traditionally used to relieve fatigue and a feeling of weakness; it contains caffeine and is unsuitable with high blood pressure or ulcers. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Eleuthero](https://herbadex.com/en/herb/eleuthero/) T Traditional use Eleutherococcus senticosus Eleuthero (Siberian ginseng) root is traditionally used for symptoms of weakness such as fatigue; do not use it for more than 2 months. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Korean Ginseng](https://herbadex.com/en/herb/korean-ginseng/) T Traditional use Panax ginseng Korean ginseng (Panax ginseng) root is traditionally used for symptoms of weakness such as fatigue; use it for no more than 3 months. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Rhodiola](https://herbadex.com/en/herb/rhodiola/) T Traditional use Rhodiola rosea Rhodiola (Rhodiola rosea) extract is traditionally used to relieve symptoms of stress such as fatigue and exhaustion in adults. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Yerba Mate](https://herbadex.com/en/herb/yerba-mate/) T Traditional use Ilex paraguariensis Traditionally used for tiredness and weakness, and to increase urine in minor urinary complaints. Contains caffeine; avoid with high blood pressure or ulcers. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Liver, Kidney & Urinary](https://herbadex.com/en/for/liver-kidney/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ## Other herbs in the same preparation form (Dried Herb & Tea) [Dried Herb & Tea →](https://herbadex.com/en/form/dried-herb-tea/) ### [Echinacea](https://herbadex.com/en/herb/echinacea/) A Strong clinical evidence Echinacea purpurea Juice pressed from fresh echinacea plants may help with short-term prevention and treatment of colds. Dried echinacea tea is not covered. [Immunity](https://herbadex.com/en/for/immunity/) [Skin & Hair](https://herbadex.com/en/for/skin-hair/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Psyllium Husk](https://herbadex.com/en/herb/psyllium-husk/) A Strong clinical evidence Plantago ovata Taken with plenty of water, psyllium husk helps soften stools in constipation; keep a gap between it and other medicines. [Digestion](https://herbadex.com/en/for/digestion/) [Heart & Circulation](https://herbadex.com/en/for/heart-circulation/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Senna](https://herbadex.com/en/herb/senna/) A Strong clinical evidence Senna alexandrina A stimulant laxative for short-term relief of occasional constipation. No longer than 1 week; not for children under 12, in pregnancy or while breastfeeding. [Digestion](https://herbadex.com/en/for/digestion/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [St. John's Wort](https://herbadex.com/en/herb/st-johns-wort/) A Strong clinical evidence Hypericum perforatum St John's wort extract may help with mild to moderate depressive episodes, but it seriously interacts with many medicines, including the pill. [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Digestion](https://herbadex.com/en/for/digestion/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) This page is for information only and is not medical advice. If you take medication, are pregnant, or have a health condition, talk to your doctor or pharmacist before use.