Any baby detergent or any that is free and clear. Don't waste your money on dreft.
I have always used baby detergent at first for at least six months but I didn't use dreft cuz it's so expensive I used purex baby it's the same thing but a lot cheaper
I use baby detergent.. im a first time mom so i dont really know.. but my nephews all had super sensitive skin when they were new born and my sisters had a heck of a time with rashes.. i also have sensitive skin and can't use certain detergents so it wont surprise me at all if my little guy does too.. i get it in the same area as regular detergent and it's pretty reasonably priced.. i think it was arouns 4 dollars if I remember correctly.. and you don't need much so a little goes a long way..