Are you staying hydrated? It's important to make sure you are drinking plenty of water. Sometimes dark urine (orange colored) can be a sign of too much zinc- so if you just started the supplements and noticed a change- it wouldn't hurt, and I'd even encourage calling your doctor to make them aware of the change. Typically someone can take 300 mgs and it is fine, but each person is unique and I'd personally rather check out something like this then just ignore it.