Menthol

Good evidence for IBS symptom relief as enteric-coated peppermint oil and for topical pain relief. One of the better-studied natural compounds for functional GI disorders.

A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.

Meta-analyses of enteric-coated peppermint oil (containing menthol as primary active) show significant benefit for IBS symptoms, particularly abdominal pain and bloating. Topical menthol activates TRPM8 receptors providing analgesic and cooling effects. NNT for IBS is approximately 4.

• Reduces IBS symptoms including abdominal pain and bloating
• Topical analgesic via TRPM8 cold receptor activation
• Antispasmodic effects on smooth muscle

Enteric-coated peppermint oil: 180-225 mg (0.2-0.4 mL oil) two to three times daily before meals for IBS. Topical: 5-16% menthol preparations as needed.

• Heartburn if non-enteric-coated
• Perianal burning
• Allergic reactions (rare)
• Skin irritation with topical use

Enteric coating is important to prevent heartburn. May worsen GERD. Not suitable for those with bile duct obstruction or gallstones. Topical use can cause skin irritation.

Benefits are specific to enteric-coated peppermint oil formulations for IBS. Non-enteric forms often cause heartburn. Topical pain relief is temporary.

• Pain50
• Recovery30