Calamus (Sweet Flag): What It Does and When to Be Careful

Calamus, also called sweet flag, smells spicy and grassy and shows up in old herbal books for digestion, focus, and muscle aches. People still use it today, but unlike chamomile or ginger, calamus comes with real safety questions. Know what it can do, what to avoid, and how to pick a safer product.

Uses and what the herb actually does

Folks traditionally brewed the dried root as tea for bloating, nausea, and mild stomach cramps. Some people use a low-strength calamus tincture for occasional digestive upset or to calm jittery nerves. The root’s aroma also makes it popular in small amounts for chewing or in incense and topical blends for sore muscles.

If you’re chasing benefits, expect subtle effects. Calamus can relax smooth muscle in the gut and has compounds that may act on the nervous system, so people report feeling calmer or less bloated after use. Don’t expect dramatic cures—think of it as a gentle support, not a replacement for medical treatment.

Safety, dosing, and buying tips

Here’s the hard part: certain calamus types contain beta-asarone, a compound that showed cancer risk in some animal studies when taken at high doses for long periods. Because of that, many agencies advise caution. Pregnant or breastfeeding people should avoid calamus. If you’re on prescription drugs, especially for the nervous system or liver, check with your provider before trying it.

Practical dosing rule: start very low. If using a dried root tea, one small pinch to a quarter teaspoon is a cautious start; if you tolerate that, one small cup a day is typical in folk use. Avoid concentrated essential oils or high-dose extracts unless an experienced herbalist or clinician recommends them. Don’t use calamus daily for months—short, occasional use is safer.

When buying, look for products that list the botanical name (Acorus calamus) and ideally state beta-asarone levels or refer to low-asarone varieties. Prefer suppliers that test for contaminants and give clear preparation instructions. Avoid essential oil labeled for internal use unless it explicitly states safe concentration and testing. Organic root material reduces pesticide risk but doesn’t change asarone content.

Want alternatives? For digestion try ginger or peppermint; for calming, consider ashwagandha or clary sage (used carefully). Those herbs have clearer safety profiles and more modern research supporting short-term use.

Curious to read related guides on this site? Check our posts on Ashwagandha Benefits, Why Clary Sage Helps Sleep and Mood, and Yerba Mansa for immunity and energy. If you're managing meds or a chronic condition, ask your clinician before adding any new herb.