Six [10, 12, 15, 16, 23, 26] out of 26 trials (23.08%) were evaluated as strong quality, the rest of 20 trials (76.928%) were evaluated as moderate quality. The majority of the included trials were assessed to be moderate methodological quality. The sample size of including trials varied from 24 to 200 patients. None of the 26 trials reported sample size calculation. Ten trials described the randomization procedure, six [10, 12, 15, 16, 23, 26] trials used random number table, four trials [8, 17, 25, 30] used visiting time to realize the randomization. One trial [23] used opaque envelopes to allocate concealment. Only four [12, 15, 23, 27] of the 26 trials employed a blinding procedure: three of them using patients blinding, doctors blinding, and assessors blinding, and the other one [27] mentioned single-blind without further details. Seven trials [8, 10-12, 15, 21, 25] reported the withdrawals/dropouts information. Three trials [13, 16, 26] mentioned follow-up, and neither of them used intention to treat method. The reporting quality of 26 trials according to quality assessment tool for quantitative studies varied among different trials (Table 3) . (Tables 4-6) 3 [9, 15, 18, 23, 30] used the percentage of HAMD scores reduced rate to measure the outcome: cure (HAMD scores reduced rate more than 75%), significant effective (HAMD scores reduced rate between 51% and 75%), effective (HAMD scores reduced rate from 25 to 50%) and ineffective (HAMD scores reduced rate less than 25%). None of the five trials showed significant difference between treatment and control group on the four criteria outcome measurement Two [17, 19] trials compared the effectiveness using the three criteria outcome measurement: significant effective (SDS scores reduced rate ≥ 50%), effective (50 > SDS scores reduced rate ≥ 30%), not effective (SDS scores reduced rate < 30%). The Total effective rate is the combination of "cure", "significant effective "and" effective rate". We put these two different kinds of measurements together to evaluate the general effectiveness. The meta-analysis showed no significant difference between xiaoyaosan and antidepressants on the Total effective rate Bupleuri 10 g, Paeoniae lactiflorae 12 g, Angelicae sinensis 12 g, Poriae cocos 20 g, Atractylodis macrocephalae 10 g, Moutan radicis 12 g, Gradeniae jasminodidis 10 g, Curcumae l2 g, Acori graminei 10 g, Fructus aurantii 10 g, Draconis 30 g, Ostreae 30 g, Polygalae tenuifoliae 12 g, Cizyphi spinosae 30 g, Tritici aestivi levis 30 g, Glycyrrhizae uralensis 10 g, Zizyphi jujubae 5. Blood stasis plus Ligustici chuanxiong 12 g, Salviae milgiorrhizae 20∼30 g; Phelgm and dampness plus Citri reticulatae 10 g, Pinelliae ternatae 10 g; Yin deficiency plus Lilii 30 g, Anemarrhenae asphodeloibis 10 g; Qi deficiency remove Gradeniae jasminodidis, plus Pseudostellariae heterophyllae 15 g; Astriction plus Cannabis sativae 10 g or Radix et rhizome 10 g