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DoctorX Dr. Fernando Caudevilla Book a consultation
Retrato del Dr. Fernando Caudevilla con sudadera naranja y fonendoscopio.

Medicine without moral judgement.

Dr Fernando Caudevilla — family physician. More than twenty years caring for people who use drugs, from scientific evidence and harm reduction, not from prejudice.

By video consultation only, by appointment. Health centre licensed by the Regional Government of Madrid, CS14162..

  • The Lancet
  • BMJ
  • EMCDDA
  • United Nations
  • International Journal of Drug Policy
  • Energy Control
  • Global Drug Policy Observatory
  • Drug Policy Alliance
  • Adiktologie

Drugs have replaced sexuality as the social taboo. We need to move past moral judgement and acknowledge how complex the relationship between people and drugs really is.

Dr. Fernando Caudevilla

Every dot is one sample analysed

Between 2014 and 2019 the International Analysis Service he led examined 5,879 samples sent in by cryptomarket users around the world. Eleven of them contained fentanyl or its derivatives in heroin: the finding reached the official reports of the United Nations.

Sample analysed Fentanyl detected
Samples analysed
0

International Analysis Service, 2014–2019

Questions answered
0

Consultorio médico abierto en criptomercados

Views on his threads
0

Entre 2013 y 2015

Years in practice
0

Medicina de familia y reducción de riesgos

El Dr. Caudevilla con bata blanca y fonendoscopio en su consulta.
Medical practice, Madrid

The doctor who chose to listen before judging

His professional interest sits where almost nobody wanted to look: at the crossing of the internet, drugs and the health of the people who use them.

He began in 2002 with a review of the effects and risks of MDMA built on more than two hundred scientific papers. From 2001, and for almost twenty years, he was medical adviser to Energy Control, the Spanish NGO that pioneered harm reduction.

In 2013 he opened a free medical clinic on the deep web under the alias DoctorX. What began as a thread titled “Ask an expert doctor about health and drugs” became the first international substance testing service for cryptomarket users.

He has spoken at conferences in eleven countries, at the trial of Ross Ulbricht and before the United Nations itself. During the pandemic he returned to front-line care at a Madrid health centre. Jose Ángel Mañas and Jordi Ledesma turned his story into the novel DoctorX: el médico de la Darknet (2024).

Leer la biografía completa

Career

Two decades of documented work, inside and outside the public health system.

  1. 2001

    Energy Control

    Medical adviser to the Spanish NGO that pioneered harm reduction with recreational drugs. Nearly twenty years of collaboration.

  2. 2002

    Review on MDMA

    Publishes a review of the effects and risks of MDMA drawing on more than two hundred scientific papers.

  3. 2013

    Clinic on Silk Road

    “Ask an expert doctor about health and drugs”. More than 130,000 views and 900 questions answered.

  4. 2015

    Juicio a Ross Ulbricht

    The defence requests his sworn statement on harm reduction, prepared with Monica Barratt and Tim Bingham.

  5. 2016

    Fentanyl alert

    Detects ocfentanil as an adulterant in heroin. The United Nations includes the report in its official documents.

  6. 2019

    International Analysis Service

    Closure of the first testing service for cryptomarket users: 5,879 samples over six years.

  7. 2020

    Pandemic and the United Nations

    Two years treating patients at a Madrid health centre. Speaks before the UN on drug policy.

  8. 2024

    Practice and community

    Private video consultation and moderation of the Dread harm reduction forum.

Selected publications

Peer-reviewed research in drug policy and public health.

  1. 2021

    Drug cryptomarkets in the 2020s: policy, enforcement, harm, and resilience

    Horton-Eddison M, Shortis P, Aldridge J, Caudevilla F

    Policy Brief 16 · Global Drug Policy Observatory

  2. 2017

    The hidden web and the fentanyl problem: detection of ocfentanil as an adulterant in heroin

    Quintana P, Ventura M, Grifell M, et al.

    International Journal of Drug Policy · 40:78–83

  3. 2016

    Results of an international drug testing service for cryptomarket users

    Caudevilla F, Ventura M, Fornís I, Barratt MJ, et al.

    International Journal of Drug Policy · 22:38–41

  4. 2016

    The emergence of deep web marketplaces: a health perspective

    Caudevilla F

    The Internet and Drug Markets · EMCDDA Insights 21

  5. 2016

    Netreach work: implementing web-based harm reduction interventions with online drug users

    Vale Pires C, Caudevilla Gálligo F, Valente H

    Adiktologie · 2:182–187

Ver el currículum completo

Private video consultation

An hour to talk about what other consultations cannot. Without moral judgement, and with verified information.

  • Comprehensive care: physical, psychological, social and emotional
  • Motivational interviewing and cognitive behavioural therapy
  • Rational use of medication, never to mask symptoms
  • Confidentiality under Spanish data protection law and Act 41/2002

First appointment

60 minutes

100 €

Follow-up

45 minutes

75 €

How to book

(+34) 608 40 70 19

Press: by SMS to the same number. WhatsApp not available.

Payment methods

  • Bank transfer
  • Bizum
  • PayPal
  • Cryptocurrency