It has been speculated that probiotics can improve athletic performance. Significant increases in haemoglobin concentration and oxygen consumption have also been shown to follow the ingestion of lactic acid bacteria in athletes. The aim of this study was to determine whether the administration of commercially prepared probiotics could influence haemoglobin concentration and other haematological parameters in moderately active males. Fifty healthy, moderately active male volunteers were divided into two groups (Test Group and Control Group). A randomized, double-blind, placebo-controlled, pre-test/post-test, group comparison study was done. The study showed no significant differences (p≥0.05) between the two groups on any of the dependent measurements. There were statistically significant changes (p≤0.05) between pre- and post-test results within the two groups. These changes were within physiological limits. Sodium increased significantly (p=0,001) from 139.29 mmol/L to 140.96 mmol/L in the Control Group. In the Test Group sodium increased significantly (p=0,035) from 139.60 mmol/L to 140.90 mmol/L, and potassium decreased (p=0.010) from 4.67 mmol/L to 4.44 mmol/L. Study results thus indicated that the ingestion of a lactic acid bacteria preparation for 42 days did not increase the haemoglobin concentration in moderately active males.