In De Gradibus, Al-Kindi attempts to apply mathematics to pharmacology by quantifying the strength of drugs. According to Prioreschi, this was the first attempt at serious quantification in medicine. He also developed a system, based on the phases of the Moon, that would allow a doctor to determine in advance the most critical days of a patient's illness. During the Arabic-Latin translation movement of the 12th century, De Gradibus was translated into Latin by Gerard of Cremona. Al-Kindi's mathematical reasoning was complex and hard to follow; Roger Bacon commented that his method of computing the strength of a drug was extremely difficult to use.
- p. 19, "Al-Kindi, A Precursor Of The Scientific Revolution", Plinio Prioreschi, Journal of the International Society for the History of Islamic Medicine 1, #2 (October 2002), pp. 17–19.
- p. 18, Prioreschi 2002.
- (incomplete citation) Klein-Franke, p. 172