As Meow said, I believe that just water is best for the first little while. (Though I occasionally used a bit of sorbelene to get rid of "sticky" poos).

I have made my own spray bottle that has water (about 400mL), 3 squirts of sorbelene and 1 very small squirt (1/2 a teaspoon) of a nicely scented baby wash in it. (At the moment its that GAIA bedtime bath). Heaps and heaps cheaper than the premade stuff. You can just buy a spray bottle from a supermarket in the gardening or cleaning area. HTHs.