Blood Agar (BA) is an enriched medium used for the cultivation of bacteria or microorganisms that do not grow easily. These bacteria are called "fastidious" because they require a special, enriched nutritional environment compared to common bacteria. Blood agar is used to grow a wide range of pathogens, especially those that are more difficult to grow, such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria species. It is also necessary to detect and differentiate haemolytic bacteria, particularly Streptococcus species. It is also a differential medium for detecting haemolysis (destruction of red blood cells) by cytolytic toxins secreted by certain bacteria, such as certain strains of Bacillus, Streptococcus, Enterococcus, Staphylococcus and Aerococcus.