The effect of herbal supplementation on the severity of exercise-induced pulmonary haemorrhage (abstract only, full study requires purchase, though one of the authors has provided the same information as a later PhD dissertation) was a study to assess the efficacy of herbal formulations designed to enhance platelet function (in this case, Yunnan Paiyao and the marvellously named Single Immortal) conducted under a randomized cross-over protocol. The study found
The herbal formulations were not effective in decreasing EIPH [...] or in changing any of the other variables measured with the exception of time-to-fatigue, which was slightly but significantly prolonged by Single Immortal compared with placebo and Yunnan Paiyao [...] Thus, these results do not support the use of these herbal formulations in the prevention of EIPH.
Yunnan Paiyao is recommended on the internet for menstrual cramps and excessive bleeding, cancerous bleeding as well as equine bleeders (EoR particularly enjoyed Steve Hart's comment - after seeking a veterinarian's advice which he disagrees with as he would "rather work with something like Yunnan Paiyao"), pet cancer (the desperate, illogical thinking of owners is clear from dalefo's willingness to accept the offer of the unused Yunnan Paiyou from another owner who's dog died shortly after buying the supply), and circulation and regularity. Single Immortal is a little harder to track down (EoR kept finding gaming sites), but the professional sounding Veterinary Institute for Integrative Medicine is still recommending it for EIPH. Mind you, this document is also full of effects such as "clears heat in the liver", "builds qi" and "moves blood and qi".
Thanks to Liz Ditz over at I Speak of Dreams for the link.