I had to look this up. Who knew?
"That’s because raw potatoes contain a toxic compound called
solanine, which could make you very sick.
Most potatoes don’t have enough solanine to kill a human, but green potatoes or any that are starting to sprout have high solanine content, which can cause symptoms including stomach pain, headache, and paralysis. You should avoid green potatoes even when they’re cooked for this reason. At the very least, consuming raw potatoes causes severe gas and bloating — and they don’t even taste good." - from cheatsheet.com