A clinical research system of coronavirus disease 2019（COVID-19） was used to collect data of 2135 COVID-19 patients with 8836 visits from February 4 th to July 12 nd

2020. Gender

age

date of onset

course of disease

onset symptoms

current symptoms

comorbid diseases

medications

prognosis

and other related information were extracted

and the corresponding traditional Chinese medicine（TCM） syndromes were determined through systematic induction and summarization of patient-related information. The results of the syndrome investigation showed that cough

low fever

fatigue

and poor appetite and digestion were the main symptoms

with white or yellow thick and greasy tongue coating

and slippery pulse. The TCM syndromes were formulated by invasion of damp toxin pestilent qi

and combined pathogens of damp and toxin. The syndrome elements included damp

heat

toxin

stasis

and deficiency; the TCM syndromes of patients from all over the country was mainly of damp toxin and showed significant regional differences. The evolution of the disease was characterized by mild and insidious initial stage but rapid transmission process

with possibility of sudden conversion to the severe cases and rapid progression; the course of the disease was stale

lingering and difficult to cure; the condition was complex and changeable. Syndrome investigation and analysis confirm that the COVID-19 belonged to "damp toxin epidemic"; "damp toxin constraint in the lung" is the core pathogenesis; the concurrent and combined diseases reflect its regional characteristics

and its clinical manifestations and evolution rules are also in line with the pathological characteristics of damp toxin.