Dizzy is a tool for stochastic and deterministic simulation of chemical reactions. Developed by the Bolouri institute in Seattle, this version of the Dizzy tool has been extended at the Laboratory for Foundations of Computer Science, Edinburgh.

The Edinburgh version extends the original with implementations of faster stochastic simulation algorithms such as the optimised direct method, the sorting direct method, and the logarithmic direct method. Users can compare the effectiveness of the stochastic simulators on the problems which interest them.

As alternatives to stochastic simulation, users can solve their models using both ordinary and stochastic differential equation solvers.

In addition, Dizzy allows users to perform sensitivity analysis on their models, in order to determine which parameters have the greatest impact on the model kinetics.

The Dizzy software is freely available for download as Java source code and runs on many hardware and software platforms.