As a Naturopath I generally recommend that a young baby requires little more than warm water to bathe in. If you did need a soap product to remove stubborn milk or food residue the use of pure organic unscented castille soap would be suitable.
Using fragrance free and additive free products are particularly important if there is a family history of atopy or allergy as the introduction of fragrances, surfactants and soaps may irritate the skin and cause a reaction.
When the baby’s hair begins to grow and requires washing the use of the castille soap or a natural baby shampoo such as those by Gaia, Eco or Burts Bees would be suitable.