Slippery Elm

Slippery elm is one of the least restricted ingredients on Australia's permitted list, and also one of the least studied. These are the questions our naturopaths ask in store, and most are about timing and what else you take.

A good fit if

• You're an adult and you're comfortable that it's based on how it works and long traditional use, not trial data
• You can take it a couple of hours apart from anything else you take
• You want the powder and don't mind a thick, slippery drink
• You'll check the botanical name on the label, or ask us to

Check with us first if

• You take any prescription medicine. Mucilage forms a thick gel in your gut, and nobody has measured whether that changes how other medicines are absorbed. Taking them a couple of hours apart is an easy precaution.
• You're being treated for Crohn's disease or ulcerative colitis. A published review of herb-drug interactions in older people with bowel disease names slippery elm, but we couldn't access its conclusion. Raise it with your gastroenterologist.
• You're pregnant or breastfeeding. There's no data either way and no official warning to go on. Folk claims point in both directions and we couldn't verify any of them, so we won't repeat them.
• It's for a child. We haven't found any data in children, and Australian labelling for a cough claim requires adults only, or medical advice for children under 2.
• Your symptoms are persistent, severe or new. Heartburn, bowel changes and a sore throat that won't settle all deserve a proper check rather than a supplement.

• Slippery elm bark powder, stirred into water. Best known for: The traditional preparation, and the one the mechanism actually describes. Absorption: Not an absorption question. The mucilage acts by contact, and it's in contact from the first mouthful. Typical use: Item 4548, and the only slippery elm item that also carries excipient status alongside active and homoeopathic.
• Slippery elm bark dry, and Ulmus rubra by its botanical name. Best known for: The same plant under the two other names you'll meet on a label. Absorption: As above. Typical use: Items 4547 and 5089. If a label gives you a binomial rather than a common name, Ulmus rubra is the one to look for.
• Capsules and tablets. Best known for: Convenience, and no texture to get past. Absorption: The gel forms in the stomach rather than coating the throat and oesophagus on the way down. Typical use: No study compares formats, so that's a mechanistic argument rather than an evidence one, and we'd rather say so.
• Lozenges. Best known for: Keeping the mucilage in contact with the throat for longer. Absorption: Same physical idea, held higher up. Typical use: Throat rather than gut. Again on mechanism, because nobody has tested it.
• Multi-herb gut or detox blends. Best known for: Slippery elm as one name on a long list. Absorption: Unknowable. The individual dose usually isn't disclosed. Typical use: The trial blend also held senna and cascara sagrada, both stimulant laxatives, so any gut effect is at least as likely to be theirs.
• Other permitted elms: americana, campestris, glabra, minor, parvifolia, pumila. Best known for: Being different species that share a genus and nothing else. Absorption: Not applicable. Typical use: Items 5083 to 5088. None of them is slippery elm, and none of slippery elm's record belongs to them.
• Ulmus macrocarpa and Ulmus davidiana. Best known for: The two elms that do have clinical trials. Absorption: Not applicable. Typical use: Neither appears anywhere in Schedule 1, and one of those studies used injection rather than a supplement. That research doesn't transfer here.

Reference values. None. Slippery elm is a herb, not a nutrient, so there's no NHMRC recommended intake for it.

Typical supplemental range. There isn't a studied dose to share. No trial has tested slippery elm on its own, and we haven't found a reliable source for a traditional amount, water volume or mixing method either. Follow the directions on your product's label.

Upper level. Australia's permitted ingredients list (Schedule 1) sets no daily dose limit and no restriction on how it's taken (items 4547, 4548 and 5089), and no maximum intake has been set by the NHMRC, FSANZ or the TGA.

Worth knowing. The only dose figure we've found is 1,350 mg a day of an eight-herb blend, and slippery elm's share wasn't disclosed, so it tells you nothing about slippery elm itself. Because there's no official limit, our advice here is based on care rather than a rule, which is a reason to take more care, not less. What you need depends on your age, diet and health, so talk to one of our naturopaths.

This list is the part of the page we will not shorten. If any of it applies to you, talk to one of our naturopaths or your doctor before starting.

• Prescription medicines. Mucilage gels in the gut and no source quantifies the effect on absorption. Separate dosing is a precaution, not a measured one.
• Inflammatory bowel disease on medication. A 2017 herb-drug interaction review discusses Ulmus rubra; the slippery elm findings weren't in the cached abstract.
• Pregnancy and breastfeeding. No human data, no Schedule 1 pregnancy warning. Unknown rather than reassuring. Unverified folk claims run both ways.
• Children. No age restriction on the ingredient, no paediatric data, and cough indications require adults only or medical advice under 2 years.
• Acute abdominal pain, nausea, vomiting or diarrhoea. Bowel-regularity indications require a do-not-use statement.
• Fluid intake. Bowel-regularity indications require a drink-plenty-of-water statement, standard for anything bulk-forming.
• Everyone. Schedule 1 imposes no warning, cap or condition here, so every caution is judgement rather than requirement.
• Species substitution. Nine Ulmus items are permitted and only three are slippery elm.