Alternatives to Dulcolax if You Can't Fill Your Prescription

Dulcolax (bisacodyl) is a reliable and fast-acting stimulant laxative, but what happens when you can't find it? Whether your pharmacy is out of stock, you had a side effect you didn't like, or you're looking for a gentler option, there are several effective alternatives. Here's a plain-English breakdown of the best Dulcolax alternatives in 2026.

First: Check If Generic Bisacodyl Is Available

Before trying a different drug, remember that Dulcolax is simply the brand name for bisacodyl. If the Dulcolax brand is out of stock, ask for generic bisacodyl — it's the exact same active ingredient at the same strength, typically available as a store brand (CVS Health, Walgreens Brand, Equate at Walmart). It works identically and costs $2-$8 versus $8-$20 for the brand.

Alternative #1: Senna (Senokot, Ex-Lax) — Best Like-for-Like Swap

Senna is another stimulant laxative that works the same way as bisacodyl — it stimulates the muscles of the intestine to cause a bowel movement. Oral onset time is similar: 6-12 hours. Senna is available as Senokot tablets, Ex-Lax chocolate squares, and many store-brand generic tablets. It's widely available at virtually every pharmacy and grocery store.

Best for: Anyone who needs a direct, same-class substitute for Dulcolax tablets.

Onset: 6-12 hours (oral tablets)

Price: $4-$12 OTC

Alternative #2: MiraLAX (Polyethylene Glycol 3350) — Best Gentle Option

MiraLAX works differently from Dulcolax. Instead of stimulating intestinal muscles, it draws water into the colon to soften stool and make it easier to pass. It's gentler, less likely to cause cramping, and safe for longer-term use than stimulant laxatives. MiraLAX takes 1-3 days to work, so it's not the right choice if you need fast relief tonight.

Best for: Gentler relief, longer-term use, or patients who can't tolerate stimulant laxatives.

Onset: 1-3 days

Price: $10-$25 OTC (30-day supply)

Alternative #3: Magnesium Hydroxide (Milk of Magnesia) — Best for Faster OTC Relief

Milk of Magnesia (magnesium hydroxide) is a saline laxative that works by pulling water into the intestine, softening stool and triggering a bowel movement in 30 minutes to 6 hours. It's faster than oral Dulcolax tablets (6-12 hours) and is available OTC at any pharmacy. It can be used for occasional constipation and works well for adults and older children.

Best for: People who want faster relief than oral bisacodyl provides.

Onset: 30 minutes to 6 hours

Price: $5-$12 OTC

Alternative #4: Docusate Sodium (Colace) — Best Stool Softener

Colace (docusate sodium) is a stool softener, not a true laxative. It doesn't stimulate the bowel; it helps water and fat mix into stool to soften it. It's much gentler than bisacodyl and works over 1-3 days. It's commonly used in hospitals and after surgery to prevent constipation rather than treat it acutely. If you need relief tonight, Colace alone is not the right choice.

Best for: Prevention of constipation, post-operative patients, or combined with a stimulant for difficult constipation.

Alternative #5: Psyllium (Metamucil) — Best for Ongoing Management

Psyllium (sold as Metamucil) is a bulk-forming fiber supplement. It's best for managing chronic constipation over time, not for acute relief. Psyllium adds bulk to stool and promotes regular bowel movements when taken daily. It's safe for daily long-term use and is recommended for people with chronic constipation who need a maintenance strategy.

Alternatives If Bisacodyl Is Part of a Colonoscopy Prep

If bisacodyl was prescribed specifically as part of a colonoscopy bowel prep (e.g., as part of the HalfLytely kit), do NOT substitute on your own. Call your gastroenterologist's office immediately — they can prescribe a different prep protocol. Common alternatives include senna tablets as the stimulant component, or a different prep kit that doesn't include bisacodyl.

Quick Comparison: Dulcolax vs. Common Alternatives

Dulcolax (bisacodyl) tablets: 6-12 hr onset, stimulant, OTC, $2-$8 generic

Senna: 6-12 hr onset, stimulant, OTC, $4-$12

MiraLAX: 1-3 day onset, osmotic, OTC, $10-$25

Milk of Magnesia: 30 min-6 hr onset, saline, OTC, $5-$12

Colace (docusate): 1-3 day onset, stool softener, OTC, $5-$15

For more information on why Dulcolax may be hard to find, see our article on Dulcolax availability in 2026. For tips on how to locate Dulcolax at a pharmacy near you, check out our guide on finding Dulcolax in stock.