The gels of Aloe species contain immunomodulatory components such as aloctin A and acemannan. Most studies on these gels were performed in in vitro cell culture systems. Although several studies examined their immunomodulatory activity in vivo, the route of administration was intraperitoneal or intramuscular. Here, we evaluated the in vivo immunomodulatory activity of processed Aloe vera gel (PAG) in mice. Oral administration of PAG significantly reduced the growth of C. albicans in the spleen and kidney following intravenous injection of C. albicans in normal mice. PAG administration also reduced the growth of C. albicans in streptozotocin-induced diabetic mice. PAG administration did not increase ovalbumin (OVA)-specific cytotoxic T lymphocyte (CTL) generation in normal mice, but did increase it in high-fat-diet induced diabetic mice. These findings provide the first clear evidence for the immunomodulatory activity of orally administered Aloe vera gel.