Did she offer a reason why? I have always understood it to be an "old time" remedy used on babies/toddler's hair, esp for growth. I have never come across anything saying it was not suitable for scalp. I put it in a homemade mixture for my post relaxer scalp and new growth. My mixture is soothing and eliminates post relaxer dry scalp. It helps to "heal" up any irritation in my scalp. If castor oil is used internally, why is it not safe for the scalp.