colonic irrigation 
noun [mass noun]
The practice of injecting water via the anus to flush out the colon, used as a therapeutic treatment: [count noun]: he waits for his colonic irrigation...
- Articles on feng shui, crystal therapy, iridology, colonic irrigation, herbalism and faith healing sweep the media every week.
- The therapist, who was born Panna Lal Palta in India, offered colonic irrigation, massages and reflexology classes.
- During their stay, they undergo regular colonic irrigation, and drink odd herbal remedies that are said to have rejuvenating properties.