Compare to the active ingredient in Gas-X Extra Strength (This product is not manufactured or distributed by GSK Consumer Healthcare, distributor of Gas-X Extra Strength). Simethicone 125 mg Antigas. Fast Relief of: pressure; bloating; discomfort. Rx - Our pharmacists recommended. Quality guaranteed or your money back. For product questions or concerns, contact us at 1-877-846-9949. Questions or Comments? Call 1-877-753-3935 Monday - Friday 9am - 5pm EST.