The aim of current study is to evaluate the possible protective role of Ketotifen against oxaliplatin-induced peripheral sensory neuropathy in patient with stage III colorectal cancer. This study will be a randomized placebo controlled parallel study.64 patients with colorectal cancer will be randomized to 2 groups: Group I (control group; n=32) which will receive 12 cycles of modified FOLFOX-6 regimen plus placebo tablets twice daily. Group II (ketotifen group; n=32) which will receive modified FOLFOX-6 regimen in addition to ketotifen 2 mg daily Blood sample collection and biochemical assessment: * Serum IL-6 as a marker of inflammation. * Serum superoxide dismutase (SOD) as a biomarker of oxidative stress. * Serum neurotensin as a biomarker for neuropathy. Assessment of oxaliplatin induced peripheral sensory neuropathy will be done through: * The implication of National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE, Version 5, 2017) for grading of neuropathy at baseline and by the end of every two oxaliplatin cycles. * The use of Neurotoxicity- 12 item questionnaire score (Ntx-12) from the validated Functional Assessment of Cancer Therapy/Gynecologic Oncology Group FACT/GOG-Ntx-12 at baseline and by the end of every two oxaliplatin cycles. * The assessment of the severity of neuropathic pain through brief pain inventory short form BPI-SF worst item. Severity of neuropathic pain will be assessed at baseline and by the end of every two oxaliplatin cycles.