After splenectomy, individuals become more susceptible to infections, particularly from encapsulated bacteria like Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis. This increased susceptibility is due to the spleen's role in producing opsonizing antibodies that target these organisms. In the context of toxicology, a compromised immune system can alter the body's ability to handle toxins and may influence the pharmacokinetics of certain drugs.