Tap water may be better than mineral water when taking pills, according to recent research

• A recent study found that only 8.7% of medication information sheets provided clear instructions on the type and amount of liquid to use when taking medication.
• The study examined 22 beverages and found that alkaline mineral water, in particular, could affect the breakdown of gastro-resistant coatings, meaning medication may be released before it reaches the intestines.
• Manipulatable medications — such as those that can be split or crushed — may break down more quickly, potentially making the liquid choice particularly important for people with dysphagia, or swallowing difficulties.
• Tap and filtered water resulted in lower medication release, potentially reducing the likelihood that they would alter the treatment’s effectiveness.

A study published in Pharmaceutics in April 2026 looked at whether different liquids could affect how medication is released in the body.

The study examined 22 beverages to determine whether any sped up the release of medication. It found that alkaline mineral water impacted the breakdown of gastro-resistant coatings.

Gastro-resistant coatings, or enteric coatings, are coatings on certain medications designed to protect the drug from stomach acid. The coating helps ensure the medication does not break down in the stomach, releasing it once it reaches the intestines.

Swallowing certain pills with vehicles such as alkaline mineral water may therefore affect how well the treatment works. Better instructions on how to take the medication, such as taking it with tap water, could help reduce this risk.