Health Guide


What is it?

Chlorella is used as a nutritional supplement. It is also thought to boost the immune system and help fight infection. It has been shown to increase the good bacteria in the gastrointestinal (GI) tract, which helps to treat ulcers, colitis, diverticulosis and Crohn's disease. It is also used to treat constipation, fibromyalgia, high blood pressure and high cholesterol. Chlorella has been used to treat cancer and also help protect the body from the effects of cancer radiation treatment.

Other names for Chlorella include: Chlorella vulgaris, Chlorella pyrenoidosa.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:

Tell your doctor if you.

  • are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement)
  • are pregnant or plan to become pregnant while using this medicine
  • are breastfeeding
  • have any other health problems, such as high blood pressure or heart or blood vessel disease


Talk with your caregiver about how much Chlorella you should take. The amount depends on the strength of the medicine and the reason you are taking Chlorella. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:

Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.


  • Do not use Chlorella if you are pregnant or breastfeeding

Side Effects:

Stop taking your medicine right away and talk to your doctor if you have any of the following side effects. Your medicine may be causing these symptoms which may mean you are allergic to it.

  • Breathing problems or tightness in your throat or chest
  • Chest pain
  • Skin hives, rash, or itchy or swollen skin

Other Side Effects:

You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine or if you have any of the following problems.

  • You are more sensitive to the sun and get sunburn more easily (2)
  • You have nausea, diarrhea or stomach cramps (5)


1. Hasegawa T, Yoshikai Y, Okuda M et al: Accelerated restoration of the leukocyte number and augmented resistance against Escherichia coli in cyclophosphamide-treated rats orally administered with a hot water extract of Chlorella vulgaris. Int J Immunophamacol 1990; 12 (8):883-891.

2. Jitsukawa K, Suizu R and Hidano A: Chlorella photosensitization. New phytophotodermatosis. Int J Dermatol 1984; 23(4):263-268.

3. Konishi F, Tanaka K, Himeno K et al: Antitumor effect induced by a hot water extract of Chlorella vulgaris (CE): resistance to Meth-A tumor growth mediated by CE-induced polymorphonuclear leukocytes. Cancer Immunol Immunother 1985; 19(2):73-78.

4. Merchant RE and Andre CA: A review of recent clinical trials of the nutritional supplement Chlorella pyrenoidosa in the treatment of fibromyalgia, hypertension, and ulcerative colitis. Altern Ther Health Med 2001; 7(3): 79-91.

5. Merchant RE, Carmack CA and Wise CM: Nutritional supplementation with Chlorella pyrenoidosa for patients with fibromyalgia syndrome: a pilot study. Phytother Res 2000; 14 (3):167-173.

6. Tanka K, Yamada A, Noda K et al: Oral administration of a unicellular green algae, Chlorealla vulgaris, prevents stress-induced ulcer. Planta Medica 1997; 63:465-466.

7. Taylor JR and Wilt VM: Probable antagonism by green tea. Ann Pharmacother 1999; 33:426-428.

Last Updated: 7/4/2018
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