Bach Flower Remedies are a total placebo, but if you believe they work for you fine.
However I would seriously caution against rejecting a conventional therapy for a medical condition.
If your IBS is aggravated by stress or emotional issues (which it so often is) reducing that stress is good, but IBS is not caused by stress, although those who suffer from it may be more sensitive to emotional issues. A change of diet may also make a huge difference as IBS sufferers frequently suffer from food intolerances as well as anxiety.
Complementary medicine has its place but diseases connected with the auto immune system should not be left entirely to alternative therapies.