Report on Agar Side Effects and Usage


Natural health supplements sometimes have unexpected side effects or interactions with medication that can lead to adverse reactions that are sometimes life threatening. The following is a list of cautions that you should be aware of before using agar (Gelidium amansii). These are referred to as drug/herb interactions.

Warning 1 – Contraindications: Do not take agar if you have a bowel obstruction, esophageal obstruction or any difficulty swallowing. Not recommended if you are pregnant or breast-feeding.

Warning 2 – Electrolyte solutions: Agar increases dehydration when used with electrolyte solutions. Experts recommend avoiding concurrent use.

Warning 3 – Tannic acids: Agar increases dehydration when taken with products containing tannic acids.

Warning 4 – Thyroid preparations: Experts recommend avoiding concurrent use because of the high iodine content in agar.

Warning 5 – Alcohol: Agar increases dehydration when taken with products containing alcohol.

Warning 5 – All oral medications: Agar forms a thick gel that may stick to oral medications in the stomach and intestines. This may decrease how much medication your body absorbs, and possibly decrease the effectiveness of your medication. To prevent this interaction, allow at least one hour between taking agar and taking your oral medication.

Used as a natural health remedy: agar is used internally for the following benefits and conditions:

  • Bulk-forming laxative

Side Effects of agar

Call your doctor if you experience any of these possible side effects of agar:

  1. abdominal pain
  2. chest pain or tightness
  3. choking (may occur if taken without enough liquid)
  4. difficulty swallowing or breathing
  5. vomiting

Other side effects may also occur when using agar. (See form below)

Agar comes as dry powder and in flakes and strips. Like most seaweed and their derivatives, agar is nutritious and contains large amounts of mucilage. In the intestines, agar absorbs water and swells, stimulating bowel activity and the elimination of feces.

As with any herb, a serious allergic reaction is possible. Seek immediate medical attention if you notice any symptoms of a serious allergic reaction. These may include a rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing.

Return to the Herb List.

For questions and answers about the side effects of herbs see the Herb Forum

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