To study the effects of different feed additives on the weaning stress of Tibetan piglets, we selected 28 healthy, 30-day-old Tibetan weaned piglets and divided them into four groups, namely, the control group (basal feed without any antibiotic additions) (Nor), the group with the addition of the antibiotic lincomycin (Ant), the group with the addition of fifteen-flavor black pills of Tibetan medicine (Tib), and the group with the addition of fecal bacterial supernatant (Fec). We measured growth performance, blood physiological indexes, and metabolomics. The results showed that the Ant, Tib, and Fec groups significantly reduced the ratio of diarrhea to feed/weight (F/G) and increased the average daily gain (ADG) compared with the Nor group (p < 0.01). The Nor group had significantly lower leukocyte counts, hemoglobin levels, and erythrocyte counts compared with the other three groups at 21 d (p < 0.05). These physiological indexes tended to stabilize at 42 d. We found that there were beneficial metabolites and metabolic pathways for gastrointestinal function. Specifically, the porphyrin metabolic pathway was elevated in the Ant group, and the tryptophan metabolic pathway was significantly elevated in the Tib and Fec groups compared with the Nor group (p < 0.05). In conclusion, adding fecal bacterial supernatant and fifteen-flavor black pills of Tibetan medicine to the feed reduced the rate of diarrhea and improved the growth performance of the piglets. Moreover, it had an effect on the microorganisms and their metabolites and pathways in the gastrointestinal tract of the animals, which might be the main reason for influencing the diarrhea rate of weaned Tibetan piglets and the growth and development of the piglets. This study provides a new approach for anti-stress applications in weaned Tibetan piglets and the development of substitute anti-products.