Sometimes called Loathsomeness or Foulness of the Body. This is not a popular meditation technique in yoga circles. When you look at the CD bin of Guardian Meditations, Buddha sells pretty well and Metta is sold out, but Foulness of the Body and Death bins are full and availabe for a discount.
You can image that this meditation might be inappropriate for some people. Someone with an eating disorder for example. This meditation is the antidote to lust. It might be a more important meditation for a 20 year old celibate monk than it is for some people. It’s the kind of meditation that you may find useful only very rarely. But lust can of course be very powerful.
If you know there is a coral snake in the jungle. You know it is rare but extremely dangerous. Better to have some antidote handy, even if you are unlikely to use it. It’s pretty strong medicine!
There’s another aspect of this meditation that I actually find more useful. That’s to look at each part of my body and notice that it is not me, not mine. I am not my spleen. I am not my sweat. But I am also not my brain. Not my heart. Where am I?