DS (2.3) used to love his bath, but earlier in the week did a poo while he was in there and it really freaked him out. We didn't make a big deal of it, I took him into his bedroom and carried on with bedtime while DH cleaned up the poo. I told him that it didn't matter and that it was nothing to worry about.
Since then he has absolutely refused to get in the bath, even crying at the thought of it before going upstairs to bed.
We've tried getting in with him - he wouldn't get in but was happy to stand next to the bath and play with the water, wash my knees etc. I've also tried sitting him on the potty before bath time (he's not potty trained yet, but will sometimes do a wee on the potty) but even if he manages something he then just asks for a clean nappy. I've tried not to make a big deal of it, but I have told him again that if he poos by accident then it doesn't matter and we will clean it up.
We went swimming earlier in the week and he happily stood under the shower there, so I'm not worried about getting him clean, but he used to really enjoy his baths - plus it was a good way of using up a spare half hour on an indoor play sort of day 
- and I'm wondering what I can try to get him back in?