To assess the current state of cancer treatment incorporating Thai traditional medicine (TTM) and to identify problems in the system, by using the health system framework of the World Health Organization.A qualitative study was conducted by interviewing three groups of people involved in the healthcare system. The groups were constructed via purposive sampling of patients with cancer, caregivers and service providers. The study groups included 37 individuals from five TTM hospitals. In-depth interviews were conducted from October 2017 to March 2018. The interview questions were developed based on the six building blocks of a health system framework. Free form answers from participants were analyzed and interpreted to develop the study conclusions.All five TTM hospitals provided treatment to patients with cancer based on provincial public health policy. The policy allows patients with cancer to obtain TTM services in outpatient and inpatient departments and via home visits; most patients used outpatient services. The TTM services were primarily provided by TTM practitioners and included massage, herbal steam, herbal compress and meditation. Herbal medicines were widely used and included Benja-amarit, an anticancer formulation made from Wat Khampramong and Phytoplex. The problems included poor acceptance of TTM practitioners by other healthcare practitioners, lack of experience among TTM practitioners in treating patients with cancer, lack of herbal medicine research trials, contamination in herbal medicine preparations and absence of practical treatment guidelines.TTM is an alternative treatment modality for patients with cancer and is supported by a national policy in Thailand. To increase accountability to patients and other practitioners, TTM treatments should be refined to rely on scientific principles and practitioners of TTM should receive academic training. Practical treatment guidelines need to be established and thoroughly disseminated to TTM practitioners.