Taking a bath is always encouraged and promoted in Islam. Islam emphasises not only the cleanliness of the soul but also that of the body. In some situations however, it has been made a prerequisite to the offering of any formal Prayer. The following are the conditions which necessitate taking a bath and where ablution alone is not enough.
In Case of Women
After each menstruation when the flow of blood has completely stopped.
After childbirth when the bleeding has finally stopped. Note: During these bleeding periods, women are not required to perform formal Prayers.
In Case of Men and Women
After seminal ejaculation or orgasm, whether resulting from conjugation or from any other cause. The same applies to night discharges during sleep.
Sexual contact between man and woman, even without ejaculation and however brief it may be.
All non-Muslims who become Muslims are also obliged to take a bath and start a new, fresh life as a Muslim.