There is a substance in potatoes known as solanine, which can be toxic in large quantities. In the kinds of potatoes you can buy in the shops, levels of solanine are very low, because the varieties are bred that way. You would have to eat several kilos of potatoes every day to come to any harm. HOWEVER, if potatoes start to turn green from exposure to light, the solanine levels rise considerably, and no-one should ever eat potatoes that have turned green.
On the other hand, potatoes have many good qualities. The type of starch they contain is known as resistant starch and has similar benefits to fibre in the diet, including reducing cholesterol. They have lots of minerals and vitamins, and 100g of potatoes can have nearly one quarter of the daily requirement for Vitamins C and B6. They contain no fat and a small amount of protein.
And they fill you up and taste good!!
So no, as far as I can see there is nothing wrong with eating potatoes. And a lot that is good. Enjoy!!