cleaning the teeth with the siwak (tooth-stick) or its modern substitute, the toothbrush, is allowed, as the prophet (peace be upon him) used to use the siwak often while fasting. it is better to avoid the use of toothpaste during fasting hours.

donating blood or unintentional vomiting does not break the fast.

kissing one's wife while fasting does not break the fast, as long as moderation is observed.

taking medicine by way of injection, nasal sprays or eye drops does not break the fast, as they are not a form of eating.

eating or drinking accidentally or out of forgetfulness does not break the fast.

bathing, swimming, or sitting in water to cool off while fasting is permissible.

for someone to rinse out the mouth or to taste food or drink which is being prepared, spitting it all back out without swallowing any of the food or drink, is also permissible. 

 swallowing one's saliva does not break the fast.