4 year old ds has diareahh (sp?) anything I can give him?....

[Northerner]

He's already soiled 3 pairs of pants today bless him. Am worried it's going to get worse and quite messy!

Have mentioned wearing a pull up to bed but he gets very upset at the thought.

I really wold not consider giving him anything to stop it, the bugs are better out of his tummy than in. If you can explain that to him.
You could try just giveing him clear fluids for 24 hours and see if that clears it up.
Poor we might.