In order to discuss the features of compatibility and application of prescriptions containing drugs of"nineteen incompatibilities" in ancient and modern times

literatures including "nineteen incompatibilities"from ancient and modern times were collected and analyzed.A total of 1

600 prescriptions were collected including 602 ancient prescriptions and 998 modern prescriptions

among which the frequency of use of Rougui（Cortex Cinnamomi）with Chishizhi（Halloysitum Rubrum） was the highest（35.00%）

followed by Renshen（Radix Ginseng） with Wulingzhi（Faeces Togopteri）（31.56%）

Dingxiang（Flos Caryophylli） with Yujin（Radix Curcumae）（17.00%）

Wutou（Radix Aconiti/Radix Aconiti Kusnezoffii） with Xijiao（Cornu Bubali）（8.88%）

and Badou（Fructus Crotonis） with Qianniu（Semen Pharbitidis）（7.00%）.Besides

the combinations of mecury with arsenic

Sanleng（Rhizoma Sparganii） with Yaxiao（Natrii Sulfas）

Sulfur with Puxiao（Natrii Sulfas）

Langdu（Stellera chamaejasme Linn） with litharge are rarely used either ancient or modern.The combination of Cortex Cinnamomi with Halloysitum Rubrum is commonly used with medicines of tonifying qi

warmimg the interior and clearing heat to treat diseases of spleen and stomach including diarrhea and abdominal pain

as well as gynecologic diseases like dysmenorrhea.The combination of Radix Ginseng with Faeces Togopteri is used with medicines of invigorating qi and strengthening the spleen

activating blood to remove stasis to treat obstetrical and gynecological diseases

malignant tumors

infantile convulsion

cardiovascular diseases

etc.The combination of Flos Caryophylli with Radix Curcumae is used with medicines of strengthening the spleen

regulating the flow of qi

resolving phlegm

and stopping coughing to treat diseases of spleen and stomach

such as hiccups and stomachaches.The results showed that under such circumstances as special symptoms and synergies

the prescription containing drugs of"nineteen incompatibilities"were used in both ancient and modern times.Therefore

the safety and compatible principles of the "nineteen incompatibilities"need further study.