Objective To develop a patient reported outcome（ PRO） scale for patients with recurrent oral ulcer under the guidance of traditional Chinese medicine（ TCM） theory. Methods According to the principle and process of PRO scale development

combined with the relevant theory of TCM

the theoretical framework of the recurrent oral ulcer PRO scale was established. The item pool was established through interviews and literature methods.The items were screened and optimized according to the expert Delphi method and the Likert evaluation method

and the pre-survey scale was formed through the cultural adaptability survey. Clinical investigation was conducted in patients with recurrent oral ulcers. The item screening was performed using discrete trend method

correlation coefficient method

factor analysis method

t test method

Cronbach α coefficient method

and expert importance score.Results Totally 78 symptoms of the pool of items were formed

and 27 items of the PRO pre-survey scale for recurrent oral ulcers were obtained after optimization. A total of 175 questionnaires were issued

and 169 copies were collected. Two items with standard deviation < 0. 7 were deleted by discrete trend method. Factor analysis method was used to remove one item close to other factors

and by Cronbach α coefficient method one item with Cronbach αcoefficient < 0. 7 was deleted. Six items with expert importance score < 8 points（ 2 of which were the same as discrete trend method） were deleted

and finally 19 items were selected to form the PRO scale of TCM recurrent oral ulcer. They were divided into 4 areas of physical

psychological

social

and independent fields

including 12 aspects of pain and discomfort

physical strength

sleep

urine and stool

diet

sweating

cold

positive feelings

negative feelings

daily life

personal ability

social relations

social environment. Conclusion The development process of TCM recurrent oral ulcer PRO scale can reflect the characteristics of the occurrence of TCM recurrent oral ulcer

reflect the quality of life of patients with recurrent oral ulcer

and further scientific assessment is needed to ensure the reliability

validity and response of the scale.