There are quite a few people for whom coriander (or cilantro if you're American) has a rather unpleasant soapy, or even metallic, taste.
The aldehydes present in coriander, as well as those similar to them, are also commonly found in both soaps and lotions.
But it's not just the chemical composition of coriander leaves that makes some find it has a soapy taste.
It is possible for people to grow to like the taste of coriander.
It's been suggested that repeated exposure to the taste leads to the brain forging new, positive associations. The strength of the aldehydes' effect on the taste of coriander can also be mitigated by crushing the leaves before consumption, with studies having shown that this speeds up the rate at which the aldehydes in the leaves are broken down by enzymes.