Here's an example showing how to flip the chart along a vertical axis.
h=barh(bins,counts); %# include previous two lines from aboveset(get(h,'Parent'),'xdir','r')
since the HISTOGRAM function was introduced (R2014b), you can make a horizontal histogram by setting 'orientation' to 'horizontal'
example:
histogram(data,'orientation','horizontal')
You can also use the regular histogram function hist and then change the point of view by typing
>> view(90, -90)