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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

Important warnings and messages

Error in v1.0. The IT calculations use a shortcut that does not work in all cases. This error will affect IT calibrations 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). It will also affect IT LPx predictions when the exposure scenario is specified with a crude resolution (the hourly resolution of FOCUS profiles will lead to negligible errors). This error is repaired in the update of the Matlab version, to v. 1.1. Download a PDF document explaining this error in detail. (posted 19 May 2020). This error is repaired in the update of the standalone and Matlab version, to v. 1.1.

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.

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.

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, at least not in the way it was used in the openGUTS Matlab version for formatting text in figures. Matlab versions up to 2022b do not have this problem. (thanks to Amund for spotting and reporting this). The update to v1.1a solves this issue (6 April 2023). However, the new version will no longer support Matlab R2014b-R2016a. If you are still on such an ancient platform, I suggest to keep working with v1.1 (the calculation engine has not changed with v1.1a).

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 in which there are one or more missing values at the last time point. The error occurs while the program tries to plot the results after the calibration. The Matlab version does not have this problem. A workaround for the standalone would be to split the data set in two, such that there are observations at the last time point for each data set. (thanks to Jan for spotting and reporting this).


  • 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.
  • Heads up! At SETAC Europe 2023 (30 April), there are two short course dealing with GUTS: general and bee-specific.
  • 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)