In this study, the objective was to ensure anti-bacterial properties for originally coloured wools with naturally sourced garlic stem extracts. In addition, zinc chloride-based treatment was also carried out. The aim was to retain the original colours of the wool fibres during these treatments. The effects of both treatments were evaluated in terms of colour changes in the wool fibres. It was found that the colour changes caused by the treatments were high in white/ecru fibres but more limited in black fibres. The colour differences between the treated and untreated black fibres were near 1; they were also quite high in white/ecru fibres. The anti-bacterial properties of the treated wool fibres against two bacteria species, one gram-negative and one gram-positive, were also investigated. It was observed that zinc chloride-based treatment ensured significant anti-bacterial efficiencies against the bacteria tested and 99.9% bacterial reduction in all cases. However, the anti-bacterial effects of garlic stem extract-based treated wool fibres were limited. It was observed that treatment of wool fibres with garlic stem extracts resulted in no anti-bacterial efficiency against Escherichia coli but did provide some anti-bacterial capability against Staphylococcus aureus. The highest bacterial reduction of S. aureus was 80.7% in originally brown-coloured wool fibre.