The ability to create horizontal error bars was added in MATLAB R2016b. You can specify the "ornt" (orientation) property of the plot to be "horizontal" to generate horizontal error bars.
For release R2016a or older
The ability to create horizontal error bars is not available in previous releases. As a workaround, you can download the user-contributed "herrorbar" function from the MATLAB Central File Exchange. You can find this file at the following URL:
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