Mild traveler diarrhea after a beach lunch — which ORS sachets do pharmacies stock and when is rest enough?

Ask for ORS or oral rehydration salts — pharmacies keep WHO-style sachets and a few local brands. Mix with clean bottled water as the packet says, sip slowly, rest, and keep to plain rice and similar until it settles. Sports drinks are not the same as ORS. If you get fever, blood, dizziness you cannot walk off, or it lasts past a couple of days, go to a clinic or hospital rather than buying more sachets. I will not invent a tourist consultation price. Mild and improving with fluids often settles with rest; worsening needs a proper look.