2. Caffeine
Caffeine makes you need the toilet more and can act both as a natural diuretic and as a natural laxative.
This is why caffeine is not a useful drink when you’re very thirsty but you should keep in mind that you can still hydrate yourself with drinks that are diuretic as in most cases you will still benefit from the fluid you take in.
Caffeine is a diuretic because it encourages the metabolism to speed up, thereby accelerating all processes in the body and encouraging you to need the toilet sooner than you otherwise would do.