Fiber Lax
Calcium Polycarbophil · Tablet, Film Coated · Oral
Active ingredient
Drug Facts Active ingredient (in each caplet) Calcium polycarbophil 625 mg (equivalent to polycarbophil 500 mg)
Purpose
Purpose Bulk-forming laxative
Uses
Uses relieves occasional constipation (irregularity) generally produces bowel movement in 12 to 72 hours
Warnings
Warnings Choking: Taking this product without adequate fluid may cause it to swell and block your throat or esophagus and may cause choking. Do not take this product if you have difficulty in swallowing. If you experience chest pain, vomiting, or difficulty in swallowing or breathing after taking this product, seek immediate medical attention. Ask a doctor before use if you have abdominal pain, nausea, or vomiting a sudden change in bowel habits that persists over a period of 2 weeks Ask a doctor or pharmacist before use if you are taking any other drug. Take Fiber-Lax two or more hours before or after other drugs. All laxatives may affect how other drugs work. When using this product
• do not use for more than 7 days unless directed by a doctor
• do not take more than 8 caplets in a 24-hour period unless directed by a doctor. Stop use and ask a doctor if you fail to have a bowel movement after use or have rectal bleeding. These could be signs of a serious condition. Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center (1-800-222-1222) right away.
Ask a doctor before use
Ask a doctor before use if you have abdominal pain, nausea, or vomiting a sudden change in bowel habits that persists over a period of 2 weeks
Ask a doctor or pharmacist
Ask a doctor or pharmacist before use if you are taking any other drug. Take Fiber-Lax two or more hours before or after other drugs. All laxatives may affect how other drugs work.
When using this product
When using this product
• do not use for more than 7 days unless directed by a doctor
• do not take more than 8 caplets in a 24-hour period unless directed by a doctor.
Stop use and ask a doctor
Stop use and ask a doctor if you fail to have a bowel movement after use or have rectal bleeding. These could be signs of a serious condition.
Keep out of reach of children
Keep out of reach of children.
Directions
Directions
• take each dose of this product with a full glass of water (8oz.) or other fluid. Taking this product without enough liquid may cause choking. See choking warning. adults and children 12 years of age and over 2 caplets, 1 to 4 times per day children under 12 years of age ask a doctor
Inactive ingredients
Inactive ingredients caramel, crospovidone, hypromellose, magnesium stearate, microcrystalline cellulose, mineral oil, polyethylene glycol, silicon dioxide, sodium lauryl sulfate, stearic acid, and talc
Questions?
Questions or comments? Call 1-800-231-4670 Monday-Friday 9AM-5PM EST
Label text from the FDA structured product label by Rugby Laboratories (revised Dec 2, 2025). Long sections are shortened; the complete label is on DailyMed.
Active ingredients
- Calcium Polycarbophil in 2 products
Fiber Lax NDC products (2)
| NDC | Strength & form | Labeler | Type |
|---|---|---|---|
| 55289-949 | Calcium Polycarbophil 625 mg/1 Tablet, Film Coated | PD-Rx Pharmaceuticals, Inc. | OTC MONOGRAPH DRUG |
| 0536-4306 | Calcium Polycarbophil 625 mg/1 Tablet, Film Coated | Rugby Laboratories | OTC MONOGRAPH DRUG |
Frequently asked questions
What is Fiber Lax used for?
Uses relieves occasional constipation (irregularity) generally produces bowel movement in 12 to 72 hours
Who makes Fiber Lax?
Fiber Lax is listed by 2 labelers in the FDA NDC directory, including PD-Rx Pharmaceuticals, Inc., Rugby Laboratories.