Do you mean from the perspective of traditional Chinese medicine or western medicine? There are many researches on spleen in TCM. Spleen deficiency generally refers to spleen deficiency, manifested as loss of appetite, pale mouth and thirst, weakness, dull complexion, salivation and other symptoms. To put it bluntly, it is a symptom of bad stomach+anemia. The most convenient way to tonify the spleen and stomach is to eat more yam, also called yam, which is regarded as diet therapy. It seems that many practices are to stew more soup and add some Chinese medicines for invigorating qi, such as Radix Astragali and Radix Codonopsis.