OBJECTIVE: In breast cancer patients, posttreatment pain often appears after several months and strongly impairs health-related quality of life. Conventional methods of pain reduction are often ineffective. Injection therapy with Traumeel (Heel GmbH, Baden-Baden, Germany), a medication with analgesic properties used in homotoxicology for treatment of the pain associated with trauma as well as a mediator of inflammation, was proposed as an innovative approach for pain relief after breast cancer treatment. DESIGN: Nine patients, still suffering from a high level of pain after breast cancer therapy despite use of postoperative treatment with conventional analgesics, were invited to participate. A Traumeel and procaine injection was administered once a week for three to 10 sessions. The level of pain was assessed by a pain score and physical and psychological status by a questionnaire before and directly after injection and again at follow-up visits after 3 and 6 months. RESULTS: After the last injection, all patients experienced a marked reduction of their level of pain on average from 7.6 +/- 1.5 to 2.4 +/- 1.4 points on a scale from 1 to 10 points. After a followup observational phase of 3 and 6 months, pain score ratings increased slightly again in some patients but remained consistently low in others. In any case, the ratings of pain levels did not reach the values assessed before the start of Traumeel injection. Similarly, health-related quality of life improved with this injection therapy. The perception of pain relief with Traumeel injection was high in 8 of 9 patients, reflecting an overall perceived positive outcome and tolerability of this treatment. CONCLUSIONS: This case series represents a first encouraging approach to using this complex homeopathic injection for pain relief in breast cancer patients.