
Dr James Alexander
Consultant Gastroenterologist & Honorary Senior Lecturer
- Available from
- London
About James Alexander
Dr Alexander completed his undergraduate medical training at the University of Cambridge and Imperial College. He was awarded his PhD for research on the role of the gut microbiome in colorectal cancer and he went on to be a NIHR academic clinical lecturer in gastroenterology at Imperial College London. He completed his specialist training in gastroenterology in the North West London region.
He performs upper and lower GI endoscopy, and conducts general gastroenterology and specialist IBD clinics including complex and joint medical/surgical IBD clinics.
Dr Alexander's research interests include exploring the role of the gut microbiota in determining colorectal cancer and IBD pathogenesis, complications and treatment responses, as well as studying the impact of IBD therapies on immune responses to vaccination. He was the lead author on the British Society of Gastroenterology (BSG) position statement on COVID-19 vaccination for patients with IBD.
He is a member of the BSG IBD Clinical Research Group and the BSG Gut Microbiota for Health expert panel. In 2023 he was awarded the British Society of Gastroenterology Young Gastroenterologist of the Year in Clinical and Translational Science.
Expertise
- Change in Bowel Habit (Constipation/Diarrhoea)
- Rectal Bleeding
- Abdominal Pain
- Abdominal Bloating
- Cancer
- Irritable Bowel Syndrome (IBS)
- Dyspepsia (Indigestion)
- Reflux (Heart Burn)
- Inflammatory Bowel Disease (Crohn's Disease And Ulcerative Colitis)
- Coeliac Disease
Overview
- Age of patients seen
- 18+
- Languages spoken
- English
- Online profiles
- Research highlights
Dr Alexanders notable publications:
Gut microbiota modulation of chemotherapy efficacy and toxicity JL Alexander, ID Wilson, J Teare, JR Marchesi, JK Nicholson, JM Kinross Nature reviews Gastroenterology & hepatology. 2017: 14 (6), 356-365 https://www.nature.com/articles/nrgastro.2017.20
International Cancer Microbiome Consortium consensus statement on the role of the human microbiome in carcinogenesis AJ Scott, JL Alexander, CA Merrifield et al. Gut. 2019: 68 (9), 1624-1632 https://gut.bmj.com/content/68/9/1624
COVID-19 vaccine-induced antibody responses in immunosuppressed patients with inflammatory bowel disease (VIP): a multicentre, prospective, case-control study JL Alexander, NA Kennedy, H Ibraheim et al. The Lancet Gastroenterology & hepatology. 2022: 7 (4), 342-352 https://www.thelancet.com/journals/langas/article/PIIS2468-1253(22)00005-X/fulltext
SARS-CoV-2 vaccination for patients with inflammatory bowel disease: a British Society of Gastroenterology Inflammatory Bowel Disease section and IBD Clinical Research Group … JL Alexander, GW Moran, DR Gaya et al. The Lancet Gastroenterology & Hepatology 2021: 6 (3), 218-224 https://www.thelancet.com/journals/langas/article/PIIS2468-1253(21)00024-8/fulltext
Pathobionts in the tumour microbiota predict survival following resection for colorectal cancer JL Alexander, JM Posma, A Scott et al. Microbiome. 2023: 11 (1), 100 https://link.springer.com/article/10.1186/s40168-023-01518-w
- Professional memberships
Member of the Royal College of Physicians (MRCP)
British Society of Gastroenterology
European Crohn's and Colitis Organisation (ECCO)
- Certifications and Awards
British Society of Gastroenterology Young Gastroenterologist of the Year (Clinical & Translational Science) 2023
Consultations and services
- Self-pay available from £250
- Health insurance
- Self-pay available from £180
- Health insurance
Insurers covered


- +1 more
- Healix
Tests & treatments
Locations
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Frequently asked questions
Yes, but only for certain services. Some consultations, assessments, and treatments can be booked directly, while others require a GP or specialist referral. Please check the relevant service page for guidance, and contact the centre if you’re unsure.
We aim to offer appointments as quickly as possible, and many services have same-day or next-day availability. Waiting times vary depending on the appointment type, specialty, and consultant availability, but our team will always offer the earliest suitable appointment.
Yes. You can arrange an appointment for a family member, or someone you care for, just let us know when you get in touch. We’ll need their details and consent to complete the booking, unless you're their legal guardian or have power of attorney.
Your first consultation includes a detailed discussion of your symptoms, medical history, and lifestyle factors, followed by a thorough examination. It’s helpful if you can bring the results of any previous investigations with you, as well as a list of your current medications. Come with a comfortably full bladder so you can provide a urine sample if requested.