Could ibs cause me to feel dehydrated? even though i drink a lot of water i feel thirsty and have dry mouth

Not usually: Unless your ibs is associated with frequent loose movements which in turn can lead to dehydration. There could be another problem leading to persistent dehydration and your physician should be consulted and blood work should be obtained.

Medications: The medications you are taking for ibs may be thecause of dry mouth. Avoid spicy and acidic foods and drinks. Use alcohol free mouth rinses.