Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom improvement
RCT	20 people in hospital with mild to moderate chronic plaque psoriasis	Mean % improvement in composite score for erythema, desquamation, and infiltration 8 weeks 54% with coal tar plus esterified essential fatty acids 56% with coal tar alone	P = 0.52 The RCT was probably too small to detect a clinically important difference between treatments The RCT found that both coal tar plus fatty acids and coal tar alone were graded as "very satisfactory or satisfactory" by 15/20 (75%) people and "very unsatisfactory or unsatisfactory" by 4/20 (20%) people when assessing ease of application, messiness, odour, and comfort		Not significant