 Diarrhea is common, may be severe, or cause dehydration or infection. At the first sign, call your doctor, start an antidiarrheal, and drink fluids. Before taking Fresenio, tell your doctor about any fever, chills, or other signs of infection. Fresenio may cause low white blood cell counts, which may cause serious infection that can lead to death. Life-threatening lung inflammation can occur. Tell your doctor about any new or worsening trouble breathing, cough, or chest pain.