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Supporting mechanistic modelling for survival

DEBtox Researc

Welcome to the openGUTS information pages

OpenGUTS is a user-friendly software to perform analyses with GUTS: the General Unified Threshold model for Survival. GUTS is the leading toxicokinetic-toxicodynamic framework for the endpoint survival (and other non-reversible all-or-nothing effects). Version 1.0 was released in December 2019, followed by Version 1.1. in February 2021.

This site hosts the software itself, as a standalone Windows executable, with manuals and background documentation. Since openGUTS is (as the name implies) open source, also the source files can be obtained here. Additionally, you can download the Matlab version, which served as the blueprint for the standalone version. The Matlab version has basically the same functionality, and can be easily adapted or extended to perform customised analyses. Finally, we provide (links to) further information on openGUTS and GUTS.

The main features of the software are:
  1. Open and free: the software is open source and freely downloadable. The fully-functional Matlab version that served as the prototype is also available.
  2. User-friendly: fit models and derive confidence intervals without requiring user interaction (e.g., no need for starting values).
  3. Robust: always find the global optimum and relevant intervals, even for awkward data sets.
  4. Flexible: allow time-varying exposure, missing data, simultaneous fitting on multiple data sets, etc.
  5. Efficient: rapid screening of exposure profiles (e.g., FOCUS output) by batch processing.
  6. Supportive: the software follows the workflow as laid down in the 2018 EFSA opinion on TKTD models.

openGUTS standalone Windows executable

Screenshot prototype small
openGUTS in Matlab


Feb. 2021. New version of the standalone launched (v1.1). The openGUTS standalone has been updated: the error has been fixed and extended batch capabilities have been included.

March 2023. New installation file for the standalone (v1.1). The installation file for the openGUTS standalone has been updated: the version of Feb. 2021 triggered a (false-positive) trojan warning by some virus scanners. We changed the packaged file docto.exe (which creates the reports) to its latest version (v. 1.8), which does not trigger this virus warning. The code for the openGUTS calculations has not changed, and there was no new compilation of the C++ code. The only change is thus a re-packaging with the new docto.exe. Downside is that the line spacing in the produced reports is increased, which does not look so nice. However, that is easily modified manually in the Word version of the report that is produced. If you have successfully installed openGUTS v. 1.1 with the previous installer, there is no need to update your installation.

Oct. 2023. OpenGUTS does not provide LCx at time points needed for EFSA's bee guidance. EFSA's 2023 bee guidance requires GUTS to be used for prediction of LCx (or LDx) after 10 and 27 days. However, these time points are not, by default, generated by openGUTS. This is easily solved in the Matlab version. In the engine folder, there is the function initial_setup.m. In Block 4 of the code (Line 159), the vector SETTINGS_PRED.T_LCx is defined, which represents the time points at which LCx are calculated. This can be modified in any way that you like, e.g., just adding 10 and 27 in there. For the standalone, this requires a new version. We will take up this point with the next update.

Important warnings/errors

Summary of errors (details on the downloads page).

Error in v1.0. The IT calculations used a shortcut that did not work in all cases. This led to errors for time varying exposure, where the exposure scenario includes episodes of linear decrease over time (for constant exposure and block pulses, it will be fine). Repaired in the update of the standalone and Matlab version, to v. 1.1.

Matlab R2023a throws errors (v1.1 and earlier). The newest version of Matlab does not allow the cell-array format for name-value pairs anymore. The update to v1.1a solves this issue (6 April 2023). However, the new version will no longer support Matlab R2014b-R2016a.

OpenGUTS standalone produces error for missing observation at last time point. The openGUTS standalone (v1.0 and v1.1) throws an error when using a data set for survival, with time-varying exposure, in which there are one or more missing values at the last time point. The Matlab version does not have this problem. A workaround is available (see downloads page).


  • 15 October 2023: added a bit more explanation on the error produced by the standalone for missing observations at the last time point. Also included an example of a data set that causes problems, and how to split up the data set as workaround. See download page.
  • 6 April 2023: new version of the Matlab version of openGUTS. This is a small update that makes openGUTS run error-free under Matlab R2023a. No changes to the calculation engine, only to the calls for plotting. See download page and the version log for details.
  • 3 March 2023: new installation file for version 1.1 of the openGUTS standalone has been released. See download page. This version does not trigger the (false-positive) trojan warning that was thrown by some virus scanners with the previous version. See more detailed explanation above.

For old news items, click here.

The openGUTS project, This site is maintained by Tjalling Jager, email: tjalling (at)