Question about dyeing hair safety?

I used Aveda madder red natural shampoo which is supposedly for red hair but i have brown hair and i used it and thought it would give me a little bit of a red glow... which it did. but i also have dark brown hair dye which i want to use and it says on the bottle not to use it if you had other reactions to dyes on your hair but techniqually the shampoo i used was all natural hair coloring and i didnt really get a reaction? should i use the dark brown hair dye or not? thanks..