Look for ones that turn blue when bruised. Also, the fundamental methodology is to start with an extremely small amount. If there are no observable effects aft

Look for ones that turn blue when bruised. Also, the fundamental methodology is to start with an extremely small amount. If there are no observable effects after some hours, eat double the amount. And repeat until there are clear effects, and decide if it's something useful. For food, for fun, or to use for poisoning enemies.