The rise in antimicrobial resistance and strict milk withdrawal regulations drive the search for safe, non-antibiotic intramammary therapies. This pilot field study focused on clinical parameters, including the somatic cell count (SCC) and the assessment of changes, as well as overall safety, which together enabled a prospective evaluation of whether the substance exerted any therapeutic effect. In this study, 48 Holstein–Friesian cows with naturally occurring clinical mastitis (somatic cell count > 400,000 cells/mL; single quarter) were randomized to receive either seven daily infusions of 10% pectin (n = 24) or two standard intramammary doses of a licensed multi-component antibiotic formulation (n = 24). The clinical severity scores (0–3) and SCC were monitored from 72 h before to 168 h after treatment initiation; the bacteriological cultures, milk TNF-α, milk yield, and blood hematology/biochemistry were also assessed. Both groups exhibited comparable and significant reductions in the mastitis scores and log2-transformed SCC by 48 h post-treatment, with equivalent bacteriological cure rates and pathogen profiles (predominantly Streptococcus uberis, coagulase-negative staphylococci, and Escherichia coli) and no local irritation, systemic adverse effects, or alterations in the milk yield, TNF-α, or blood parameters. These findings indicate that intramammary pectin at a 10% concentration is safe and well tolerated and that it provides efficacy equivalent to standard antibiotic therapy, supporting its potential as an alternative mastitis treatment that avoids antibiotic residues and contributes to antimicrobial stewardship.