Well, from a dog safety angle at least, it appears to be ok to use, and apparently also has the added benefit of being hypotensive, which by rights should reduce internal bleeding:
'The plant's traditional use for hypertension has been explored by research as well. The hypotensive effects were first reported in a dog study in 1952 (in which a diuretic effect was noted also). The hypotensive effects were attributed to a specific phytochemical in chanca piedra called geraniin in a 1988 study. In 1995 Indian researchers gave human subjects with high blood pressure chanca piedra leaf powder in capsules and reported a significant reduction in systolic blood pressure, a significant increase in urine volume and sodium excretion. Chanca piedra's diuretic effect in humans was recorded as far back as 1929 and, in India, a tablet of chanca piedra (called Punarnava) is sold as a diuretic there.'