Best OTC Medicines for Constipation
Common over-the-counter options for constipation, with typical adult dosing and key safety notes.
Reviewed by a licensed pharmacist.
Bisacodyl
5-15mg by mouth at bedtime as needed, OR 10mg suppository for faster onset. Oral onset 6-12 hours; suppository 15-60 minutes. Limit to occasional use (not daily, not >7 days).
Calcium Polycarbophil
1250mg by mouth 1-4 times daily with 8oz water, max 5000mg/day. Take with adequate fluid to prevent choking or intestinal blockage.
Docusate
100mg by mouth 1-3 times daily with plenty of water. Best for softening stool when straining is the main issue (post-surgery, hemorrhoids, hard stool); not as effective as a true laxative.
Glycerin Suppository
1 suppository rectally as needed, up to once daily. Moisten with water before insertion. Effect typically occurs within 15-60 minutes.
Magnesium Citrate
200-400mg by mouth once daily or in divided doses. Take with full glass of water. May cause diarrhea or abdominal cramping.
Methylcellulose
2g (1 tablespoon) mixed in 8oz water, 1-3 times daily. Must drink adequate fluids throughout the day. Effects may take 12-72 hours.
Peg 3350
17 grams (1 capful or 1 packet) dissolved in 4-8 oz of water, juice, or coffee, once daily. Most people see results in 1-3 days. Limit to 7 days OTC self-treatment.
Psyllium
1 rounded teaspoon (or 1 packet) in 8 oz water 1-3 times daily. Always take with a full glass of water. Onset is gradual (12-72 hours).
Saline Enema
1 enema (118mL) rectally as needed, retain 2-5 minutes before evacuating. Max 1 dose per day unless directed by physician. May cause cramping or urgency.
Senna
17.2-34.4mg of sennosides by mouth at bedtime as needed. Onset 6-12 hours. Limit to occasional use (not daily, not >7 days).
This page is for general education and is not medical advice. It does not replace a consultation with a licensed pharmacist or your clinician. Always read and follow the product label. If symptoms are severe, worsening, or persistent, seek professional care.