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Nutrition and daily life

Oolong: between green and black

Oolong is a partly oxidised tea: its taste can be fresh like green tea or deep like black. This section explains what oolong is and how to drink it during treatment.

Last updated: ~1 min read
Oolong, between green and black
Figure 1.Oolong, between green and black.

01Short answer

Oolong is made by partly oxidising the leaves, so it sits between green and black tea. Its caffeine is moderate. In ordinary amounts it is generally safe. Oolong can be brewed several times in short steeps, but in one sitting: do not keep wet leaves for later. Do not trust slimming-tea claims. Oolong is not a treatment.

02Simple explanation

Oolong is a partly oxidised tea.

Its taste lies between green and black.

Moderate caffeine.

Do not keep wet leaves for later.

03Scientific explanation

Processing: the leaves are tossed so their edges oxidise, then heated and rolled; oxidation can range from 10% to 70%.

NCI: it has not been shown in people that tea prevents or treats cancer.

MedlinePlus: about 400 mg of caffeine a day is generally considered safe for adults; during treatment watch your sleep and heart rate.

04What happens in the body?

Types

There are lightly oxidised floral oolongs and dark roasted ones.

Unfurled oolong leaves on a white dish.
Figure 2.Green centre, brown edge.

Re-steeping

Several short steeps in one sitting are fine; do not keep wet leaves for hours, as germs can grow.

Golden oolong pouring from a clay teapot into a cup.
Figure 3.Hot oolong from a clay teapot.

Safe brewing

Freshly boiled water, a clean teapot and a fresh brew. During neutropenia avoid cold tea that has stood for hours.

Iron and medicines

Drink tea about an hour after meals; do not take extract capsules without your doctor.

05Brewing: four steps

Sealed pack, fresh brew, right temperature, drink hot.

Sealed pack — Dry place.1Sealed packDry place.
Fresh brew — Not old cold tea.2Fresh brewNot old cold tea.
Right water — Boiled.3Right waterBoiled.
Drink soon — Do not keep.4Drink soonDo not keep.
FlavourTradition.
FluidsA warm drink.
SafetyBoiled water.

06Key points at a glance

TopicIn brief
TypesThere are lightly oxidised floral oolongs and dark roasted ones.
Re-steepingSeveral short steeps in one sitting are fine; do not keep wet leaves for hours, as germs can grow.
Safe brewingFreshly boiled water, a clean teapot and a fresh brew. During neutropenia avoid cold tea that has stood for hours.
Iron and medicinesDrink tea about an hour after meals; do not take extract capsules without your doctor.

07Key terms

Partial oxidation
Darkening of only part of the leaf.
Short steep
Repeated brews of a few minutes.
Caffeine
A stimulant.
Polyphenols
Antioxidant plant compounds.
Neutropenia
Low neutrophils.

08Key points

  • Oolong sits between green and black.
  • Caffeine is moderate.
  • Do not keep wet leaves.
  • Brew with boiled water.
  • Capsules only with your doctor.

09Frequently asked questions

Does oolong help weight loss?

There is no reliable evidence; discuss weight changes during treatment with your doctor.

How many times can I brew it?

Several times in one sitting, then throw the leaves away.

Does this tea treat leukemia?

No. Tea is a pleasant drink, not a treatment.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Does oolong help weight loss?

  2. How many times can I brew it?

  3. Does this tea treat leukemia?

My questions

12Sources

  1. National Center for Complementary and Integrative Health (NIH). Green Tea
  2. Memorial Sloan Kettering Cancer Center — About Herbs. Green Tea
  3. MedlinePlus. Caffeine
  4. Leukemia & Lymphoma Society. Diet Guidelines for Immunosuppressed Patients
  5. National Cancer Institute. Diet and Cancer Risk
  6. MedlinePlus (U.S. National Library of Medicine). Dietary Fiber
  7. NHS. How to get more fibre into your diet
  8. Harvard T.H. Chan School of Public Health — The Nutrition Source. Fiber
  9. British Dietetic Association. Fibre: Food Fact Sheet
  10. American Cancer Society. Eating Problems
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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