There is no evidence to support the use of oral supplements in the treatment of breast engorgement, but there are studies on the use of supplements to increase or decrease breast milk production, as found on the lactation page.
Sunflower lecithin is commonly used in the context of breast engorgement to prevent clogged milk ducts by making breast milk “less sticky”. However, there are no controlled trials to support this claim. Similarly, probiotics, specifically Lactobacillus salivarius and Lactobacillus fermentum, are sometimes used during breast engorgement to prevent mastitis, but high-quality evidence for this practice does not yet exist.[1][2]