Thanks to the effort of the research community at /r/theSilphRoad we now finally have a initial table of PokeStop drop rates and potential drops. Last updated on 04.08.2016.

Do note that this data is not conclusive for levels higher than 24. Check our Item Rewards Per Level chart also.

PokeStop drop rates

Item Total drops Implied Probability
Poké Ball 396 56.3%
Great Ball 85 12.1%
Ultra Ball 27 3.8%
Potion 55 7.8%
Super Potion 25 3.6%
Hyper Potion 9 1.3%
Revive 56 8.0%
Razz Berry 51 7.2%

 

Note: Eggs are not going to be considered toward this analysis because it seems they do not count toward the normal item drop number. The minimum number of items a PokeStop can drop is 3 and we never found an egg as third item, but only as fourth or more.