Chinese herbal medicine (CHM) is widely used in breast cancer, but there is no consensus on the Chinese medicine (CM) syndromes in the different conventional treatment stages (preoperative, postoperative, chemotherapy, radiation therapy and endocrine therapy) of early breast cancer. This Delphi study aimed to achieve expert consensus on the CM syndromes, signs and symptoms, and the Chinese herbal formulae for early breast cancer.Thirty senior CM clinicians with expertise in managing breast cancer were enrolled. The syndromes selected by ≥50% of experts and the corresponding most common Chinese herbal formulae were considered a consensus. Consensus on signs and symptoms was defined as a median score ≥4 (the item was important or very important) and ≥70% of experts rating the sign or symptom as 4 (important) or 5 (very important) on a 5-point Likert scale.Three survey rounds were conducted from 15 October 2021 to 10 March 2022. Consensus was reached with 3 syndromes confirmed for each treatment stage. Several syndromes, such as dual deficiency of qi and Blood, were considered common to multiple treatment stages. Some important signs and symptoms were presented in multiple treatment stages (eg, shortage of qi in the radiation therapy and endocrine therapy stages).This Delphi study achieved consensus on the most common CM syndromes, corresponding signs and symptoms, and the most common formulae in each treatment stage of early breast cancer, providing an evidence-based approach for future clinical practice.