I just finished a bottle of water (cambel back with straw type) and noticed black (mold?) in the straw. do i need to go to the hospital or can i take pepto?

No: Do you otherwise feel ok? I would disinfect the camel bak bladder or buy a new one. Drink plenty of water and monitor your symptoms. You should be fine. This actually happens far more common than you would think. Make it a habit of cleaning your hydration systems. I only put plain water in mine, which helps to prevent this, but it still needs cleaning.

See pharmacist: Activated charcoal capsules work as an adsorbent, not an absorbent. Speak with the pharmacist about it's use and dosage. It will bind with anything that you just swallowed, and prevent its absorption. It's also non-toxic. However pepto-bismol only coats the stomach surface, but will not bind to the black mold, nor prevent absorption as well. The activated charcoal will, and you'll poop it out black. Can still take it to hours later, and it will be effective.