The efficacy of the Diphoterine solution has been shown to be effective in a two-year study on humans and also in a study on animals. Its effectiveness as compared to use of water alone, and therefore its necessity, has been questioned by some medical experts. On the other hand these statements do not provide any studies that compare the effectiveness of the Diphoterine solution compare to water. The largest case series reported to date does compare the effectiveness of water and the Diphoterine solution. "One hundred eighty cases of alkali splashes to the skin were evaluated clinically. Two groups were compared; those who had applied Diphoterine first and those who had applied water first." Here are the results of this independent study: "There were no signs of chemical burn in 52.9% of the group who applied Diphoterine first compared with 21.4% of the group who applied water first. Only 7.9% of the group who applied Diphoterine first had blisters or more severe signs compared with 23.8% of the group who applied water first. The differences were statistically significant (P < 0.001). After implementation of Diphoterine the "first aid" injury rate for chemical burns fell 24.7% (95% CI 0.5–43.0%)."